diff --git a/lib/src/domain/auth/auth_failure.dart b/lib/src/domain/auth/auth_failure.dart
index 5b08fc6..235c7a1 100644
--- a/lib/src/domain/auth/auth_failure.dart
+++ b/lib/src/domain/auth/auth_failure.dart
@@ -1,3 +1,4 @@
+import 'package:firebase_auth/firebase_auth.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
 part 'auth_failure.freezed.dart';
@@ -14,4 +15,5 @@ abstract class AuthFailure with _$AuthFailure {
   const factory AuthFailure.malformed() = EmailMalformed;
   const factory AuthFailure.userDisabled() = UserDisabled;
   const factory AuthFailure.tooManyRequests() = TooManyRequests;
+  const factory AuthFailure.linkMergeConflict(AuthCredential credentialForLinking) = LinkMergeConflict;
 }
diff --git a/lib/src/domain/auth/auth_failure.freezed.dart b/lib/src/domain/auth/auth_failure.freezed.dart
index 91e0211..356ffc6 100644
--- a/lib/src/domain/auth/auth_failure.freezed.dart
+++ b/lib/src/domain/auth/auth_failure.freezed.dart
@@ -46,6 +46,13 @@ class _$AuthFailureTearOff {
   TooManyRequests tooManyRequests() {
     return const TooManyRequests();
   }
+
+// ignore: unused_element
+  LinkMergeConflict linkMergeConflict(AuthCredential credentialForLinking) {
+    return LinkMergeConflict(
+      credentialForLinking,
+    );
+  }
 }
 
 // ignore: unused_element
@@ -61,6 +68,7 @@ mixin _$AuthFailure {
     @required Result malformed(),
     @required Result userDisabled(),
     @required Result tooManyRequests(),
+    @required Result linkMergeConflict(AuthCredential credentialForLinking),
   });
   @optionalTypeArgs
   Result maybeWhen<Result extends Object>({
@@ -71,6 +79,7 @@ mixin _$AuthFailure {
     Result malformed(),
     Result userDisabled(),
     Result tooManyRequests(),
+    Result linkMergeConflict(AuthCredential credentialForLinking),
     @required Result orElse(),
   });
   @optionalTypeArgs
@@ -84,6 +93,7 @@ mixin _$AuthFailure {
     @required Result malformed(EmailMalformed value),
     @required Result userDisabled(UserDisabled value),
     @required Result tooManyRequests(TooManyRequests value),
+    @required Result linkMergeConflict(LinkMergeConflict value),
   });
   @optionalTypeArgs
   Result maybeMap<Result extends Object>({
@@ -95,6 +105,7 @@ mixin _$AuthFailure {
     Result malformed(EmailMalformed value),
     Result userDisabled(UserDisabled value),
     Result tooManyRequests(TooManyRequests value),
+    Result linkMergeConflict(LinkMergeConflict value),
     @required Result orElse(),
   });
 }
@@ -156,6 +167,7 @@ class _$CancelledByUser implements CancelledByUser {
     @required Result malformed(),
     @required Result userDisabled(),
     @required Result tooManyRequests(),
+    @required Result linkMergeConflict(AuthCredential credentialForLinking),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -164,6 +176,7 @@ class _$CancelledByUser implements CancelledByUser {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return cancelledByUser();
   }
 
@@ -177,6 +190,7 @@ class _$CancelledByUser implements CancelledByUser {
     Result malformed(),
     Result userDisabled(),
     Result tooManyRequests(),
+    Result linkMergeConflict(AuthCredential credentialForLinking),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -198,6 +212,7 @@ class _$CancelledByUser implements CancelledByUser {
     @required Result malformed(EmailMalformed value),
     @required Result userDisabled(UserDisabled value),
     @required Result tooManyRequests(TooManyRequests value),
+    @required Result linkMergeConflict(LinkMergeConflict value),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -206,6 +221,7 @@ class _$CancelledByUser implements CancelledByUser {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return cancelledByUser(this);
   }
 
@@ -220,6 +236,7 @@ class _$CancelledByUser implements CancelledByUser {
     Result malformed(EmailMalformed value),
     Result userDisabled(UserDisabled value),
     Result tooManyRequests(TooManyRequests value),
+    Result linkMergeConflict(LinkMergeConflict value),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -276,6 +293,7 @@ class _$ServerError implements ServerError {
     @required Result malformed(),
     @required Result userDisabled(),
     @required Result tooManyRequests(),
+    @required Result linkMergeConflict(AuthCredential credentialForLinking),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -284,6 +302,7 @@ class _$ServerError implements ServerError {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return serverError();
   }
 
@@ -297,6 +316,7 @@ class _$ServerError implements ServerError {
     Result malformed(),
     Result userDisabled(),
     Result tooManyRequests(),
+    Result linkMergeConflict(AuthCredential credentialForLinking),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -318,6 +338,7 @@ class _$ServerError implements ServerError {
     @required Result malformed(EmailMalformed value),
     @required Result userDisabled(UserDisabled value),
     @required Result tooManyRequests(TooManyRequests value),
+    @required Result linkMergeConflict(LinkMergeConflict value),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -326,6 +347,7 @@ class _$ServerError implements ServerError {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return serverError(this);
   }
 
@@ -340,6 +362,7 @@ class _$ServerError implements ServerError {
     Result malformed(EmailMalformed value),
     Result userDisabled(UserDisabled value),
     Result tooManyRequests(TooManyRequests value),
+    Result linkMergeConflict(LinkMergeConflict value),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -397,6 +420,7 @@ class _$EmailAlreadyInUse implements EmailAlreadyInUse {
     @required Result malformed(),
     @required Result userDisabled(),
     @required Result tooManyRequests(),
+    @required Result linkMergeConflict(AuthCredential credentialForLinking),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -405,6 +429,7 @@ class _$EmailAlreadyInUse implements EmailAlreadyInUse {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return emailAlreadyInUse();
   }
 
@@ -418,6 +443,7 @@ class _$EmailAlreadyInUse implements EmailAlreadyInUse {
     Result malformed(),
     Result userDisabled(),
     Result tooManyRequests(),
+    Result linkMergeConflict(AuthCredential credentialForLinking),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -439,6 +465,7 @@ class _$EmailAlreadyInUse implements EmailAlreadyInUse {
     @required Result malformed(EmailMalformed value),
     @required Result userDisabled(UserDisabled value),
     @required Result tooManyRequests(TooManyRequests value),
+    @required Result linkMergeConflict(LinkMergeConflict value),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -447,6 +474,7 @@ class _$EmailAlreadyInUse implements EmailAlreadyInUse {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return emailAlreadyInUse(this);
   }
 
@@ -461,6 +489,7 @@ class _$EmailAlreadyInUse implements EmailAlreadyInUse {
     Result malformed(EmailMalformed value),
     Result userDisabled(UserDisabled value),
     Result tooManyRequests(TooManyRequests value),
+    Result linkMergeConflict(LinkMergeConflict value),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -523,6 +552,7 @@ class _$InvalidEmailAndPasswordCombination
     @required Result malformed(),
     @required Result userDisabled(),
     @required Result tooManyRequests(),
+    @required Result linkMergeConflict(AuthCredential credentialForLinking),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -531,6 +561,7 @@ class _$InvalidEmailAndPasswordCombination
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return invalidEmailAndPasswordCombination();
   }
 
@@ -544,6 +575,7 @@ class _$InvalidEmailAndPasswordCombination
     Result malformed(),
     Result userDisabled(),
     Result tooManyRequests(),
+    Result linkMergeConflict(AuthCredential credentialForLinking),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -565,6 +597,7 @@ class _$InvalidEmailAndPasswordCombination
     @required Result malformed(EmailMalformed value),
     @required Result userDisabled(UserDisabled value),
     @required Result tooManyRequests(TooManyRequests value),
+    @required Result linkMergeConflict(LinkMergeConflict value),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -573,6 +606,7 @@ class _$InvalidEmailAndPasswordCombination
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return invalidEmailAndPasswordCombination(this);
   }
 
@@ -587,6 +621,7 @@ class _$InvalidEmailAndPasswordCombination
     Result malformed(EmailMalformed value),
     Result userDisabled(UserDisabled value),
     Result tooManyRequests(TooManyRequests value),
+    Result linkMergeConflict(LinkMergeConflict value),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -644,6 +679,7 @@ class _$EmailMalformed implements EmailMalformed {
     @required Result malformed(),
     @required Result userDisabled(),
     @required Result tooManyRequests(),
+    @required Result linkMergeConflict(AuthCredential credentialForLinking),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -652,6 +688,7 @@ class _$EmailMalformed implements EmailMalformed {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return malformed();
   }
 
@@ -665,6 +702,7 @@ class _$EmailMalformed implements EmailMalformed {
     Result malformed(),
     Result userDisabled(),
     Result tooManyRequests(),
+    Result linkMergeConflict(AuthCredential credentialForLinking),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -686,6 +724,7 @@ class _$EmailMalformed implements EmailMalformed {
     @required Result malformed(EmailMalformed value),
     @required Result userDisabled(UserDisabled value),
     @required Result tooManyRequests(TooManyRequests value),
+    @required Result linkMergeConflict(LinkMergeConflict value),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -694,6 +733,7 @@ class _$EmailMalformed implements EmailMalformed {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return malformed(this);
   }
 
@@ -708,6 +748,7 @@ class _$EmailMalformed implements EmailMalformed {
     Result malformed(EmailMalformed value),
     Result userDisabled(UserDisabled value),
     Result tooManyRequests(TooManyRequests value),
+    Result linkMergeConflict(LinkMergeConflict value),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -764,6 +805,7 @@ class _$UserDisabled implements UserDisabled {
     @required Result malformed(),
     @required Result userDisabled(),
     @required Result tooManyRequests(),
+    @required Result linkMergeConflict(AuthCredential credentialForLinking),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -772,6 +814,7 @@ class _$UserDisabled implements UserDisabled {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return userDisabled();
   }
 
@@ -785,6 +828,7 @@ class _$UserDisabled implements UserDisabled {
     Result malformed(),
     Result userDisabled(),
     Result tooManyRequests(),
+    Result linkMergeConflict(AuthCredential credentialForLinking),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -806,6 +850,7 @@ class _$UserDisabled implements UserDisabled {
     @required Result malformed(EmailMalformed value),
     @required Result userDisabled(UserDisabled value),
     @required Result tooManyRequests(TooManyRequests value),
+    @required Result linkMergeConflict(LinkMergeConflict value),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -814,6 +859,7 @@ class _$UserDisabled implements UserDisabled {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return userDisabled(this);
   }
 
@@ -828,6 +874,7 @@ class _$UserDisabled implements UserDisabled {
     Result malformed(EmailMalformed value),
     Result userDisabled(UserDisabled value),
     Result tooManyRequests(TooManyRequests value),
+    Result linkMergeConflict(LinkMergeConflict value),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -885,6 +932,7 @@ class _$TooManyRequests implements TooManyRequests {
     @required Result malformed(),
     @required Result userDisabled(),
     @required Result tooManyRequests(),
+    @required Result linkMergeConflict(AuthCredential credentialForLinking),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -893,6 +941,7 @@ class _$TooManyRequests implements TooManyRequests {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return tooManyRequests();
   }
 
@@ -906,6 +955,7 @@ class _$TooManyRequests implements TooManyRequests {
     Result malformed(),
     Result userDisabled(),
     Result tooManyRequests(),
+    Result linkMergeConflict(AuthCredential credentialForLinking),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -927,6 +977,7 @@ class _$TooManyRequests implements TooManyRequests {
     @required Result malformed(EmailMalformed value),
     @required Result userDisabled(UserDisabled value),
     @required Result tooManyRequests(TooManyRequests value),
+    @required Result linkMergeConflict(LinkMergeConflict value),
   }) {
     assert(cancelledByUser != null);
     assert(serverError != null);
@@ -935,6 +986,7 @@ class _$TooManyRequests implements TooManyRequests {
     assert(malformed != null);
     assert(userDisabled != null);
     assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
     return tooManyRequests(this);
   }
 
@@ -949,6 +1001,7 @@ class _$TooManyRequests implements TooManyRequests {
     Result malformed(EmailMalformed value),
     Result userDisabled(UserDisabled value),
     Result tooManyRequests(TooManyRequests value),
+    Result linkMergeConflict(LinkMergeConflict value),
     @required Result orElse(),
   }) {
     assert(orElse != null);
@@ -962,3 +1015,160 @@ class _$TooManyRequests implements TooManyRequests {
 abstract class TooManyRequests implements AuthFailure {
   const factory TooManyRequests() = _$TooManyRequests;
 }
+
+abstract class $LinkMergeConflictCopyWith<$Res> {
+  factory $LinkMergeConflictCopyWith(
+          LinkMergeConflict value, $Res Function(LinkMergeConflict) then) =
+      _$LinkMergeConflictCopyWithImpl<$Res>;
+  $Res call({AuthCredential credentialForLinking});
+}
+
+class _$LinkMergeConflictCopyWithImpl<$Res>
+    extends _$AuthFailureCopyWithImpl<$Res>
+    implements $LinkMergeConflictCopyWith<$Res> {
+  _$LinkMergeConflictCopyWithImpl(
+      LinkMergeConflict _value, $Res Function(LinkMergeConflict) _then)
+      : super(_value, (v) => _then(v as LinkMergeConflict));
+
+  @override
+  LinkMergeConflict get _value => super._value as LinkMergeConflict;
+
+  @override
+  $Res call({
+    Object credentialForLinking = freezed,
+  }) {
+    return _then(LinkMergeConflict(
+      credentialForLinking == freezed
+          ? _value.credentialForLinking
+          : credentialForLinking as AuthCredential,
+    ));
+  }
+}
+
+class _$LinkMergeConflict implements LinkMergeConflict {
+  const _$LinkMergeConflict(this.credentialForLinking)
+      : assert(credentialForLinking != null);
+
+  @override
+  final AuthCredential credentialForLinking;
+
+  @override
+  String toString() {
+    return 'AuthFailure.linkMergeConflict(credentialForLinking: $credentialForLinking)';
+  }
+
+  @override
+  bool operator ==(dynamic other) {
+    return identical(this, other) ||
+        (other is LinkMergeConflict &&
+            (identical(other.credentialForLinking, credentialForLinking) ||
+                const DeepCollectionEquality()
+                    .equals(other.credentialForLinking, credentialForLinking)));
+  }
+
+  @override
+  int get hashCode =>
+      runtimeType.hashCode ^
+      const DeepCollectionEquality().hash(credentialForLinking);
+
+  @override
+  $LinkMergeConflictCopyWith<LinkMergeConflict> get copyWith =>
+      _$LinkMergeConflictCopyWithImpl<LinkMergeConflict>(this, _$identity);
+
+  @override
+  @optionalTypeArgs
+  Result when<Result extends Object>({
+    @required Result cancelledByUser(),
+    @required Result serverError(),
+    @required Result emailAlreadyInUse(),
+    @required Result invalidEmailAndPasswordCombination(),
+    @required Result malformed(),
+    @required Result userDisabled(),
+    @required Result tooManyRequests(),
+    @required Result linkMergeConflict(AuthCredential credentialForLinking),
+  }) {
+    assert(cancelledByUser != null);
+    assert(serverError != null);
+    assert(emailAlreadyInUse != null);
+    assert(invalidEmailAndPasswordCombination != null);
+    assert(malformed != null);
+    assert(userDisabled != null);
+    assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
+    return linkMergeConflict(credentialForLinking);
+  }
+
+  @override
+  @optionalTypeArgs
+  Result maybeWhen<Result extends Object>({
+    Result cancelledByUser(),
+    Result serverError(),
+    Result emailAlreadyInUse(),
+    Result invalidEmailAndPasswordCombination(),
+    Result malformed(),
+    Result userDisabled(),
+    Result tooManyRequests(),
+    Result linkMergeConflict(AuthCredential credentialForLinking),
+    @required Result orElse(),
+  }) {
+    assert(orElse != null);
+    if (linkMergeConflict != null) {
+      return linkMergeConflict(credentialForLinking);
+    }
+    return orElse();
+  }
+
+  @override
+  @optionalTypeArgs
+  Result map<Result extends Object>({
+    @required Result cancelledByUser(CancelledByUser value),
+    @required Result serverError(ServerError value),
+    @required Result emailAlreadyInUse(EmailAlreadyInUse value),
+    @required
+        Result invalidEmailAndPasswordCombination(
+            InvalidEmailAndPasswordCombination value),
+    @required Result malformed(EmailMalformed value),
+    @required Result userDisabled(UserDisabled value),
+    @required Result tooManyRequests(TooManyRequests value),
+    @required Result linkMergeConflict(LinkMergeConflict value),
+  }) {
+    assert(cancelledByUser != null);
+    assert(serverError != null);
+    assert(emailAlreadyInUse != null);
+    assert(invalidEmailAndPasswordCombination != null);
+    assert(malformed != null);
+    assert(userDisabled != null);
+    assert(tooManyRequests != null);
+    assert(linkMergeConflict != null);
+    return linkMergeConflict(this);
+  }
+
+  @override
+  @optionalTypeArgs
+  Result maybeMap<Result extends Object>({
+    Result cancelledByUser(CancelledByUser value),
+    Result serverError(ServerError value),
+    Result emailAlreadyInUse(EmailAlreadyInUse value),
+    Result invalidEmailAndPasswordCombination(
+        InvalidEmailAndPasswordCombination value),
+    Result malformed(EmailMalformed value),
+    Result userDisabled(UserDisabled value),
+    Result tooManyRequests(TooManyRequests value),
+    Result linkMergeConflict(LinkMergeConflict value),
+    @required Result orElse(),
+  }) {
+    assert(orElse != null);
+    if (linkMergeConflict != null) {
+      return linkMergeConflict(this);
+    }
+    return orElse();
+  }
+}
+
+abstract class LinkMergeConflict implements AuthFailure {
+  const factory LinkMergeConflict(AuthCredential credentialForLinking) =
+      _$LinkMergeConflict;
+
+  AuthCredential get credentialForLinking;
+  $LinkMergeConflictCopyWith<LinkMergeConflict> get copyWith;
+}
diff --git a/lib/src/infrastructure/firebase_auth_facade.dart b/lib/src/infrastructure/firebase_auth_facade.dart
index f195957..7c72857 100644
--- a/lib/src/infrastructure/firebase_auth_facade.dart
+++ b/lib/src/infrastructure/firebase_auth_facade.dart
@@ -175,8 +175,7 @@ class FirebaseAuthFacade implements AuthFacade {
         accessToken: googleAuthentication.accessToken,
       );
 
-      await _firebaseAuth.signInWithCredential(authCredential);
-      return const Auth.success();
+      return signInWithCredential(authCredential);
     } catch (e) {
       debugPrint(e);
       return const Auth.failure(AuthFailure.serverError());
@@ -197,8 +196,7 @@ class FirebaseAuthFacade implements AuthFacade {
         accessToken: googleAuthentication.accessToken,
       );
 
-      await _firebaseAuth.signInWithCredential(authCredential);
-      return const Auth.success();
+      return signInWithCredential(authCredential);
     } on FirebaseAuthException catch (e) {
       debugPrint(e.toString());
       return const Auth.failure(AuthFailure.serverError());
@@ -219,10 +217,19 @@ class FirebaseAuthFacade implements AuthFacade {
   @override
   Future<Auth> signInWithCredential(AuthCredential credential) async {
     try {
-      await _firebaseAuth.signInWithCredential(credential);
-      return const Auth.success();
+      if (_firebaseAuth.currentUser == null) {
+        await _firebaseAuth.signInWithCredential(credential);
+        return const Auth.success();
+      } else {
+        debugPrint("Already signed in, attempting to link current user with credential.");
+        await _firebaseAuth.currentUser.linkWithCredential(credential);
+        return const Auth.success();
+      }
     } on FirebaseAuthException catch (e) {
       debugPrint(e.toString());
+      if (e.code == "credential-already-in-use") {
+        return Auth.failure(AuthFailure.linkMergeConflict(e.credential));
+      }
       return const Auth.failure(AuthFailure.serverError());
     } catch (e) {
       debugPrint(e.toString());
@@ -234,10 +241,17 @@ class FirebaseAuthFacade implements AuthFacade {
   Future<Auth> signInWithOAuth(String provider, List<String> scopes,
       Map<String, String> parameters) async {
     try {
-      await FirebaseAuthOAuth(app: _app)
-          .openSignInFlow(provider, scopes, parameters);
-      return const Auth.success();
+      final firebaseAuthOAuth = FirebaseAuthOAuth(app: _app);
+      if (_firebaseAuth.currentUser == null) {
+        await firebaseAuthOAuth.openSignInFlow(provider, scopes, parameters);
+        return const Auth.success();
+      } else {
+        debugPrint("Already signed in, attempting to link current user with credential.");
+        await firebaseAuthOAuth.linkExistingUserWithCredentials(provider, scopes, parameters);
+        return const Auth.success();
+      }
     } on PlatformException catch (e) {
+      // TODO Merge accounts on link failure
       /**
        * The plugin has the following error codes:
        * 1. FirebaseAuthError: FirebaseAuth related error
diff --git a/lib/src/presentation/lit_auth_ui.dart b/lib/src/presentation/lit_auth_ui.dart
index e3858c0..fed6daf 100644
--- a/lib/src/presentation/lit_auth_ui.dart
+++ b/lib/src/presentation/lit_auth_ui.dart
@@ -68,6 +68,9 @@ class LitAuthState extends StatelessWidget {
 /// TypeDef callback for authentication failure
 typedef AuthFailureCallback = void Function(AuthFailure failure);
 
+/// TypeDef callback for link merge conflicts
+typedef LinkMergeConflictCallback = void Function(LinkMergeConflict conflict);
+
 class LitAuth extends StatelessWidget {
   /// Configure the sign-in UI and provide custom decoration/configuration for
   /// the sign-in elements. Leaving this empty will show the standard sign-in
@@ -89,6 +92,9 @@ class LitAuth extends StatelessWidget {
 
   /// Callback to be called if authentication fails
   final AuthFailureCallback onAuthFailure;
+  
+  /// Callback to be called to handle link merge conflicts
+  final LinkMergeConflictCallback onLinkMergeConflict;
 
   /// Configuration for custom error notifications
   final NotificationConfig errorNotification;
@@ -145,6 +151,7 @@ class LitAuth extends StatelessWidget {
     this.config,
     this.onAuthSuccess,
     this.onAuthFailure,
+    this.onLinkMergeConflict,
     this.errorNotification = const NotificationConfig(),
     this.successNotification = const NotificationConfig(),
   }) : super(key: key);
@@ -183,6 +190,7 @@ class LitAuth extends StatelessWidget {
     return _SignInBuilder(
       onAuthFailure: onAuthFailure,
       onAuthSuccess: onAuthSuccess,
+      onLinkMergeConflict: onLinkMergeConflict,
       errorNotification: errorNotification,
       successNotification: successNotification,
       child: StandardSignInWidget(
@@ -197,6 +205,7 @@ class _SignInBuilder extends StatelessWidget {
     Key key,
     @required this.onAuthFailure,
     @required this.onAuthSuccess,
+    @required this.onLinkMergeConflict,
     this.builder,
     @required this.errorNotification,
     @required this.successNotification,
@@ -205,6 +214,7 @@ class _SignInBuilder extends StatelessWidget {
 
   final VoidCallback onAuthSuccess;
   final AuthFailureCallback onAuthFailure;
+  final LinkMergeConflictCallback onLinkMergeConflict;
   final TransitionBuilder builder;
   final NotificationConfig errorNotification;
   final NotificationConfig successNotification;
@@ -236,29 +246,44 @@ class _SignInBuilder extends StatelessWidget {
               WidgetsBinding.instance
                   .addPostFrameCallback((_) => onAuthFailure(f.failure));
             }
-            WidgetsBinding.instance.addPostFrameCallback(
-              (_) => NotificationHelper.error(
-                context: context,
-                config: errorNotification,
-                message: f.failure.map(
-                    cancelledByUser: (_) => 'Cancelled',
-                    serverError: (_) => 'Server error',
-                    emailAlreadyInUse: (_) => 'Email already in use',
-                    invalidEmailAndPasswordCombination: (_) =>
-                        'Invalid email and password combination',
-                    malformed: (_) => 'Not a valid email address',
-                    userDisabled: (_) =>
-                        'User disabled. Contact customer care for assistance',
-                    tooManyRequests: (_) =>
-                        'Too many unsuccessful login attempts. Please try again later'),
-              ).show(context),
-            );
+            if (onLinkMergeConflict != null) {
+              // Skip showing error if link merge conflicts are handled
+              f.failure.maybeWhen(
+                  linkMergeConflict: (credential) => WidgetsBinding.instance
+                      .addPostFrameCallback((_) => onLinkMergeConflict(f.failure)),
+                  orElse: () { showError(context, f.failure); }
+              );
+            } else {
+              showError(context, f.failure);
+            }
           },
         );
       },
     );
   }
 
+  void showError(BuildContext context, AuthFailure failure) {
+    WidgetsBinding.instance.addPostFrameCallback(
+          (_) =>
+          NotificationHelper.error(
+            context: context,
+            config: errorNotification,
+            message: failure.map(
+              cancelledByUser: (_) => 'Cancelled',
+              serverError: (_) => 'Server error',
+              emailAlreadyInUse: (_) => 'Email already in use',
+              invalidEmailAndPasswordCombination: (_) =>
+              'Invalid email and password combination',
+              malformed: (_) => 'Not a valid email address',
+              userDisabled: (_) =>
+              'User disabled. Contact customer care for assistance',
+              tooManyRequests: (_) =>
+              'Too many unsuccessful login attempts. Please try again later',
+              linkMergeConflict: (_) => 'Account already exists for sign in method',),
+          ).show(context),
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     return StateNotifierProvider<SignInHandlerStateNotifier,
@@ -288,6 +313,7 @@ class _LitAuthCustom extends LitAuth {
     Key key,
     VoidCallback onAuthSuccess,
     AuthFailureCallback onAuthFailure,
+    LinkMergeConflictCallback onLinkMergeConflict,
     NotificationConfig errorNotification = const NotificationConfig(),
     NotificationConfig successNotification = const NotificationConfig(),
     this.builder,
@@ -296,6 +322,7 @@ class _LitAuthCustom extends LitAuth {
           key: key,
           onAuthSuccess: onAuthSuccess,
           onAuthFailure: onAuthFailure,
+          onLinkMergeConflict: onLinkMergeConflict,
           errorNotification: errorNotification,
           successNotification: successNotification,
         );
@@ -308,6 +335,7 @@ class _LitAuthCustom extends LitAuth {
     return _SignInBuilder(
       onAuthSuccess: onAuthSuccess,
       onAuthFailure: onAuthFailure,
+      onLinkMergeConflict: onLinkMergeConflict,
       builder: builder,
       errorNotification: errorNotification,
       successNotification: successNotification,