Peters Pool is a small sandy lagoon ringed by reef at the end of Napier Street in North Cottesloe, and one of the most popular snorkelling spots in Perth. It is part of the Cottesloe Reef Fish Habitat Protection Area and offers easy access straight from the beach, depths of 2–5 m and plenty of fish.

The reef around the lagoon is weathered limestone with ledges, holes and overhangs. Snorkel Spots lists toadfish, striped grunter, whiting, damselfish, monocle bream, gold-lined bream, goatfish, leatherjackets, old wives, red-lipped morwong and stripeys, and schools of fish are common even on days of poor visibility. Rays rest on the sand.

It is easy enough for children and beginners to stay in the shallow lagoon, while more confident snorkellers and divers can explore the outer reef. Conditions change through the day: westerly winds typically worsen visibility by midday, and currents can be noticeable around tide changes.

The main difficulty is its popularity. On summer weekends parking is hard to find and the lagoon is crowded, so go early or midweek. Facilities, including toilets, showers, cafes and shade, are available at North Cottesloe and Cottesloe.

Peters Pool suits families, snorkellers and new divers. Experienced divers usually find it too shallow for scuba, but it is pleasant for a relaxed dip or an easy night snorkel in calm weather.

Water temperatures on this coast range from about 17 °C in late winter to 22–23 °C in late summer, when the warm Leeuwin Current is strongest, so a 5 mm wetsuit suits summer and a 7 mm suit with a hood is more comfortable from June to October.

Drive to North Cottesloe and park in the small car park at the end of Napier Street, right at Peters Pool, or along Marine Parade; parking fills early on warm days. Buses stop nearby, and Cottesloe and Grant Street train stations are within walking distance. Walk down to North Cottesloe Beach and enter directly into the sandy lagoon, then snorkel or dive out to the reef around it.

Cottesloe Beach's main facilities are about 700 m south.

Best with easterly or light winds and low swell. Westerly winds usually spoil visibility by midday. Currents can push snorkellers around, so smaller tides or times near slack water are better.

Winter swell and storms make the lagoon rough and murky. The south-westerly sea breeze arrives most summer days around midday, so the best window is early morning.

Enter from the beach into the lagoon, snorkel or dive around its reef rim in 2–5 m, then explore the outer edges on a calm day. Return to the beach at the same point.

No operator; one of Perth's most popular independent snorkel spots in summer.