Several Picton-based operators run dolphin swim and watch trips out into Queen Charlotte Sound and beyond into Cook Strait. The most commonly encountered species is the dusky dolphin, which forms huge pods in the strait, with occasional sightings of bottlenose, common, and very rarely the world's smallest dolphin — the threatened Hector's dolphin.
Sightings are not guaranteed (the operators usually offer a partial refund or a free re-trip if no dolphins are seen) but the strike rate is high in summer. Swimming with dolphins requires reasonable confidence in the water and a wetsuit, both provided; the water temperature in Cook Strait stays under 18°C even in February. Trips run from October to April.