Marble Arch is a boat-launched Tofo dive built around a sandy bowl, two archways, and a donut-shaped reef with walls that rise from the bottom. It works well for open-water divers who want to practice buoyancy while moving through swim-throughs, and it also gives macro hunters plenty to look at in the cracks and gullies. Seasonal highlights include rays, guitarfish, nudibranchs, and bigger marine visitors such as whale sharks and manta rays when the Tofo conditions line up.