diff --git a/borgmatic/hooks/mongodb.py b/borgmatic/hooks/mongodb.py
index 1cbd98f..f8432b1 100644
--- a/borgmatic/hooks/mongodb.py
+++ b/borgmatic/hooks/mongodb.py
@@ -143,7 +143,7 @@ def build_restore_command(extract_process, database, dump_filename, connection_p
     Return the mongorestore command from a single database configuration.
     '''
     hostname = connection_params['hostname'] or database.get('restore_hostname', database.get('hostname'))
-    port = str(connection_params['port'] or database.get('restore_port', database.get('port')))
+    port = str(connection_params['port'] or database.get('restore_port', database.get('port', '')))
     username = connection_params['username'] or database.get('restore_username', database.get('username'))
     password = connection_params['password'] or database.get('restore_password', database.get('password'))
 
diff --git a/borgmatic/hooks/mysql.py b/borgmatic/hooks/mysql.py
index b5218dc..f64f16f 100644
--- a/borgmatic/hooks/mysql.py
+++ b/borgmatic/hooks/mysql.py
@@ -201,7 +201,7 @@ def restore_database_dump(database_config, log_prefix, location_config, dry_run,
     database = database_config[0]
 
     hostname = connection_params['hostname'] or database.get('restore_hostname', database.get('hostname'))
-    port = str(connection_params['port'] or database.get('restore_port', database.get('port')))
+    port = str(connection_params['port'] or database.get('restore_port', database.get('port', '')))
     username = connection_params['username'] or database.get('restore_username', database.get('username'))
     password = connection_params['password'] or database.get('restore_password', database.get('password'))
 
diff --git a/borgmatic/hooks/postgresql.py b/borgmatic/hooks/postgresql.py
index 8672028..08b0019 100644
--- a/borgmatic/hooks/postgresql.py
+++ b/borgmatic/hooks/postgresql.py
@@ -222,7 +222,7 @@ def restore_database_dump(database_config, log_prefix, location_config, dry_run,
     database = database_config[0]
 
     hostname = connection_params['hostname'] or database.get('restore_hostname', database.get('hostname'))
-    port = str(connection_params['port'] or database.get('restore_port', database.get('port')))
+    port = str(connection_params['port'] or database.get('restore_port', database.get('port', '')))
     username = connection_params['username'] or database.get('restore_username', database.get('username'))
 
     all_databases = bool(database['name'] == 'all')