Erscott's Hole is one of the classic Lord Howe lagoon snorkel sites and one of the island's marine sanctuary areas. The DAN account of diving Lord Howe describes Erscott's Hole and Comet's Hole as circular pools about 7 m deep with coral walls, and the island's tourism site gives a maximum depth of about 8 m and a five-minute boat ride from the boatsheds.

The hole is a sand-floored pool ringed by coral on the lagoon floor, and it acts as a gathering place for fish. Spacifica's species list shows how much variety fits into a small space: Lord Howe Island bluefish, doubleheader wrasse, spangled emperor, neon damsels, Coleman's pygmy seahorse, Foster's hawkfish, spotted snake eels and beaked leatherjackets. Divernet notes it as a marine sanctuary area, and Islander Cruises runs daily trips to it as part of the southern sanctuary zone, which it calls home to 'the greatest diversity of coral reefs and fish species' in the lagoon.

Because it is inside the lagoon, the site is suitable in nearly all weather and is used by both snorkel boats and the dive shop. Visibility is typically around 10 m in summer inside the lagoon – lower than outside the reef – but the shallow depth means colours are bright. The pygmy seahorse and other small species reward divers who take their time.

It suits everyone from first-time snorkellers to experienced divers looking for macro subjects. Scuba divers should keep off the coral walls and control buoyancy near the sand, as fine sediment clouds easily.

Lord Howe is reached only by air: QantasLink flies from Sydney daily (about 1 h 50 min), with Brisbane and seasonal Port Macquarie services. Accommodation must be booked before flights (visitor numbers are capped at about 400) and the checked-baggage limit is 14 kg, so most divers hire gear on the island. The lagoon sites are reached from the Lagoon Road boatsheds: Dive Lord Howe's boat is moored in the lagoon and reaches the holes in about 5 minutes, and glass-bottom and snorkel boats (Islander Cruises, Marine Adventures, Lord Howe Environmental Tours and others) run daily trips.

Snorkellers can also hire kayaks at the boatsheds, but the holes are well offshore near the barrier reef, so a guided boat is the practical option.

The lagoon is protected by the fringing barrier reef on the island's western side and is diveable in almost all weather, which is why operators use it when the outer reef is closed. Strong westerly and south-westerly winds – mainly with winter fronts – make it choppy and push swell over the reef, stirring the sand and cutting visibility. The holes are deep enough to dive at any tide, but the surrounding lagoon floor is very shallow at low tide and boats time runs accordingly.

Visibility is usually around 10–20 m (lower than outside the reef), and water is warmest from January to April.

Snorkellers float over the rim and the coral walls; divers descend to the sand at 7–8 m and circle the pool slowly just off the coral wall, then rise to explore the rim for small fish.

Dive Lord Howe – lagoon dives used daily as a sheltered option and for courses; snorkel and glass-bottom boat tours by Islander Cruises (daily access to the southern and northern sanctuaries), Marine Adventures, Lord Howe Environmental Tours, Reef N Beyond and Liv For The Sea.