Associate Professor Bryan Grieg Fry, a prominent venom expert, has clarified the error: "The hook nosed myth was due to a fundamental error in a book called 'Snakes in question'.

The belcher's sea snake is of moderate size, ranging from 0.5 to 1 meter (about 20–40 inches) in adult length.

Its thin body is usually chrome yellowish in colour with dark greenish crossbands.

Hydrophis comes from Greek ὕδωρ, hydōr = water + ὄφις, ophis = serpent.

The specific name, belcheri, commemorates the Nova Scotian, Royal Navy Captain, later Admiral, Sir Edward Belcher KCB, RN (1799-1877)[11] who collected the holotype.