The S-Bahn line S1 runs directly from Rostock Hauptbahnhof to Warnemünde in about 20 minutes, with trains running frequently throughout the day. This is by far the easiest and most practical way to arrive — the station drops you right in the centre of the resort, a short walk from both the Alter Strom and the beach.
By car, Warnemünde is roughly 12 km north of central Rostock via the B103. Parking near the beach and Alter Strom can be difficult and expensive in summer; the train is strongly recommended during peak season.
Warnemünde is also the starting and ending point of ferry crossings to Gedser in Denmark, operated by Scandlines. The ferry terminal is at the northern tip of the Alter Strom, a short walk from the lighthouse.