The beach is just at the end of the port, and can be reached by walking, or by car or taxi. Many of the hotels (i.e. Hotel Santa Caterina or Hotel Miramalfi) have a shuttle to town or to the port that can be used if you are staying at those hotels. So, once you reach there it is around a 4 minute walk (some will even drop you at your desired destination if you ask). If you rented a car and plan on driving there, there is public parking right outside the beach club. It is about a 10 minute walk from the Hotel Santa Caterina area. You can make a right out of the hotel, and follow the street along the right hand side until you reach a tunnel. There is a pedestrian walking path on the right side of the tunnel (do not walk through the tunnel). Follow that path, and you will come upon stairs that lead down to the port. Take those stairs down, until you reach the port area, and then make a right. You can follow that road to the end to reach Lido Delle Sirene.