You can go through the north Swamp exit through a tunnel to Bayjin and go into the Bayjin Shallows map from there, which connects with the same underwater tunnel map you reach from Mt. Gigas; from that map you can reach (with just a bit of difficulty...heh) the Sea Caves. Faster to go from from Mt. Gigas, but probably worth going at least partway through Bayjin for all the experience.
|