Las Tintoreras sits just off Puerto Villamil, close enough to reach by water taxi but wild enough to feel like a proper Galapagos outing. White-tip sharks rest in a narrow lagoon, and the surrounding water is good for snorkelling with turtles, rays and reef fish.
It is a neat half-day choice if you do not have time or budget for Los Tuneles, though the two experiences are different enough to justify doing both.