Beyond the shipwrecks, the outer barrier reef encircling Chuuk Lagoon offers some of the best coral wall diving in Micronesia. The reef drops away in vertical walls from 3 metres to depths well beyond recreational limits, with hard coral gardens giving way to massive barrel sponges, sea fans, and black coral forests in the deeper sections.
The outer reefs are accessed primarily by liveaboard. Because they see far fewer divers than the wrecks, the fish life is notably wilder — grey reef sharks patrol the wall tops, large schools of snapper and surgeonfish move through the current, and hammerheads are occasionally spotted in the blue water beyond the drop-off. The passages through the barrier reef generate strong currents that attract pelagic species and make for exhilarating drift dives. For divers who want a break from wreck penetration, the outer reef is a refreshing contrast.