Meet the site
Horsburgh Island is the uninhabited island at the north-western corner of the southern atoll, about 1 km² of coconut palms and sand no more than 2 m above sea level, named after the hydrographer James Horsburgh who charted the islands in the early 1800s. Its main attraction ashore is historical: during the Second World War the Ceylon Garrison Artillery installed two six-inch guns at the southern point for coastal defence, and they remain in place today, listed on the Commonwealth Heritage List. Lagoon tours stop here to see the guns and snorkel the shallow reef along the shore, and Cocos Blue Charters includes Horsburgh on its half-day history and snorkelling trips. Underwater, the lagoon side has shallow coral patches over sand with reef fish, small blacktip reef sharks and turtles, while the island's outer reefs host some of Cocos' best dive sites – Cologne Gardens and Lynnies Leap to the west, Garden of Eden to the north, and Cabbage Patch and Rose Wall to the south-east near the Western Boat Passage. The Phaeton wreck lies about a nautical mile south-east of the island in Port Refuge, and the Catalina JX435 site between Horsburgh and Direction Island, so a boat trip can combine several heritage sites. Snorkelling here is best treated as part of a tour rather than a destination in its own right; public documentation of specific snorkel spots around the island is limited. The passage beside the island has tidal flow and boat traffic, so snorkellers should stay on the lagoon side close to the shore.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Horsburgh Island is recorded as Island in Cocos (Keeling) Islands. The listed access is boat (day trip). Confirm the actual meeting point, route and permission to visit; a map pin does not establish any of these.
Topics flagged by the stored research
These are questions prompted by the existing notes, not a verified or complete hazard assessment.
- Current and timing
- Ask how the operator assesses the current window for the actual route. Historical tide notes are not a departure instruction.
- Other water users
- Ask about vessel activity, exclusion areas and the agreed surface arrangements.
Historical access notes exist for this record, but have not been independently verified for current use. Request current directions from the operator or site manager rather than following an old entry description.
Questions, answered
Is Horsburgh Island suitable for my certification?
The record lists Snorkel/Any. That does not establish suitability for every route or day. Share your training, recent experience and equipment needs with the operator and ask about the specific proposed dive.
Can I book Horsburgh Island through YouDive?
YouDive is an independent research directory. Contact an operator directly to confirm whether it currently runs the trip, the inclusions and the booking terms.
What you might see
Reef fish, juvenile blacktip reef sharks, green turtles, parrotfish, hard corals; seabirds ashore
Location
Uninhabited island on the north-western corner of the southern atoll, with WWII six-inch guns on its southern point and shallow reef around it.
Facilities nearby
None; bring water and shade.
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
en.wikipedia.orgen.wikipedia.orgaustraliantraveller.comwesternaustralia.commuseum.wa.gov.auRecord updated 27 Sept 2026. Source claims are being reviewed.
