Allas Sea Pool is a lido type of spa near the center of Helsinki. The sea pool has three pools built on the sea: regular pool, sea water pool and children’s pool. There are also saunas and cafeteria.
The pools are open year round and especially on the wintertime the experience is pretty nice. The sea pool is not heated in the wintertime so if you´d like to know what ice swimming feels like, this is pretty close to that.
The pool is very close to the center so by foot is the easiest if you are in the center. Also tram #2 has a stop close to the pool.