You can swim with the tuna in enclosures. You can see the circular tuna nets out beyond Boston Island. Each can hold up to 3,000 tuna, with little room for anyone to jump in with them. The swim with Tuna platforms are purpose built, and have enough tuna so you can fit in as well. Tuna are large fish, with constantly open mouths, and they can swim up to 80km/h when darting for a pilchard. Swimming with them isn't a calm snorkelling experience, but rather a slightly freaky experience with tuna darting rapidly at you, and then turning away with precision accuracy as they avoid everything that isn't a pilchard. Wetsuits, gloves and booties are supplied if you want to dive in.