What sets our Espíritu Santo tour apart: certified marine biologists as guides, hotel pickup and drop-off, and the only boat on this route with an on-board toilet. This is the Gulf of California, the sea Jacques Cousteau called the world's aquarium.

Sea lion swimming is regulated to protect the colony: in-water encounters run September through May. From June to August, during their breeding season, we observe the colony from the boat and add extra reef snorkelling time, when underwater visibility is at its very best.

We close the day at Balandra. Access is limited by the protected-area authority, so this is a 25-minute stop at Mexico's most photographed beach — time for the view and your photos, not for an afternoon of swimming. Balandra deserves its own day, and we run one.

Wildlife is wild — dolphins, whales, mobula rays and sea turtles appear often, but no sighting can ever be guaranteed.