North Seymour topography consists of gradual steps descending from the island shoreline, declining 8 meters to a beautiful rock reef, before reaching the sandy bottom at 16–18 meters. Diving at Seymour provides the opportunity to swim with many white and blacktip reef sharks, as well as being a favorite resting place for large numbers of green sea turtles. Though Seymour is not as famous for hammerhead sharks as other sites, it is still possible to see small schools at both Seymour sites, swimming along the current.

Large schools of barracuda, snapper, and other reef fish are also in abundance, and the rock reef is an excellent place to search for well-camouflaged octopi. A personal favorite of ours, however, are the schools of spotted eagle rays that glide through the channel just above the sand, occasionally joined by devil and manta rays.

Mosquera and its fringing rock reef is similar to Seymour until you reach the large sandy-bottomed platform and rock drop of around 21 meters. Here you can relax underwater and wait for the schools of magnificent eagle rays, hammerhead sharks, blacktip reef sharks, and the occasional, elusive, Galapagos shark. Manta rays are a special treat anywhere and sightings at Mosquera are certainly a possibility. On the sandy-bottomed platform you will be amazed by the Galapagos garden eels — thousands of them, as far as the eye can see, craning out of their tunnels to take in all the currents have to offer.