Meet the site
Three Mile Opening – TMO to the crews – is a far-northern site visited on Mike Ball's Far North Coral Sea Exploratory and Raine Island expeditions. Mike Ball describes upwelling currents that attract schooling trevally, barracuda, mackerel, tuna and sharks, with mantas and eagle rays at the continental shelf; Scuba Diver Life notes TMO features bommie maze formations. Openings are gaps in the outer barrier through which tidal water moves between the Coral Sea and the lagoon behind the reef. At the shelf edge these flows create upwellings, drawing nutrient-rich deep water to the surface and triggering plankton blooms that attract fish. The result is some of the most pelagic-rich diving on the reef: big schools of trevally and barracuda, hunting mackerel and tuna, and sharks cruising the edges. The bommie maze gives divers structure to shelter behind when the current runs, and the gaps between bommies create interesting navigation. Mantas and eagle rays are drawn to the plankton. Current is the main consideration, and operators time dives carefully. The site requires Advanced certification or equivalent experience. TMO suits experienced divers looking for pelagic action in a remote setting. It is typically dived on the same day as Creech Reef on Mike Ball's exploratory itinerary. Getting here is itself an expedition: the far-northern reefs lie hundreds of kilometres north of Cairns, are visited by only a handful of liveaboards in the October–December window, and are many hours from medical help, so divers should be current, self-sufficient, carry an SMB and audible signal, and dive conservatively.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Three Mile Opening (TMO) is recorded as Drift in Far Northern Reef & Torres Strait. The listed access is boat (multi-day/liveaboard). 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.
- Water movement
- Ask how swell and local exposure affect the proposed entry, exit and route.
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 Three Mile Opening (TMO) suitable for my certification?
The record lists Advanced Open Water. 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 Three Mile Opening (TMO) 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
Giant trevally, chevron barracuda, Spanish mackerel, dogtooth tuna, grey reef sharks, manta rays, eagle rays
Location
A reef opening on the far-northern continental shelf where upwelling currents attract schooling pelagics; features a maze of bommies.
Facilities nearby
None – expedition liveaboard only (Spoilsport/Spirit of Freedom provide air, nitrox, meals, cabins).
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
mikeball.comscubadiverlife.comRecord updated 26 Sept 2026. Source claims are being reviewed.