Catchers Mitt is a site on the Tijou and Cat reef system in the far-northern Great Barrier Reef, visited on Mike Ball's Northern Exposure expeditions. Mike Ball describes it as including gullies with hard corals and fish populations. Gully (spur-and-groove) topography is typical of outer reef faces.

The gullies channel water and sediment and are lined with hard corals, while the ridges between them provide structure for fish. The name suggests a curved, cupped shape – a reef bay or amphitheatre that catches current and fish like a baseball mitt. Expect a range of reef fish in the gullies and pelagic visitors on the outer edge.

The far-northern reefs are rich in sharks, turtles and schooling fish. Depths and coordinates are not published. Operators require Advanced certification or equivalent experience for these expeditions.

Catchers Mitt suits experienced divers who enjoy exploring reef structure. It complements the wall dives at Tijou and Cat reefs. 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.

On Mike Ball's Northern Exposure itineraries the Tijou and Cat reefs are dived over a day of the seven-night voyage between Cairns and Horn Island, typically with up to four dives including a night dive, and the exact sites chosen depend on the weather on the day.

Liveaboard only – there are no day boats, resorts or public moorings this far north. Mike Ball Dive Expeditions' Spoilsport runs 7-night 'Northern Exposure' expeditions between Cairns (Trinity Wharf) and Horn Island in the Torres Strait each November (northbound and southbound, up to 27 dives), plus a 7-night Far North Coral Sea Exploratory round trip from Cairns in October. Spirit of Freedom runs 7-night far-north expeditions from Cairns in October–December, and Professional Dive Services' MV Kalinda has run longer (13-night) Cairns–Horn Island trips.

Horn Island has daily scheduled flights to Cairns (book separately; allow 24 hours after diving before flying). The far-northern reefs are roughly 500–650 km north of Cairns – one to two days' steaming each way.

The far-northern reefs are only diveable in a narrow weather window. The south-east trades blow hard from about April to September and make the long open-water passage and the exposed outer walls impractical, so expeditions run in the transition period, typically October–December, when winds are lighter; the northerly monsoon, storms and cyclones (December–April) close the season. Even in the window, exposed shelf-edge walls (Tijou, Great Detached, Raine) need calm days, and skippers switch between reefs to find shelter.

Strong tidal currents and upwellings run along the continental shelf and through reef openings – channel sites are timed to slack water. Visibility varies from about 12 m to 40 m+ depending on tides and any rain. Marine stingers are present from November.

Explore the hard-coral gullies at 10–18 m, following them seaward towards the wall and back, watching for fish schools; ascend over the reef top for the safety stop.

Liveaboard only: Mike Ball Dive Expeditions (Spoilsport – 7-night Northern Exposure Cairns↔Horn Island, November; 7-night Far North Coral Sea Exploratory, October); Spirit of Freedom (7-night far-north expeditions, October–December); Professional Dive Services MV Kalinda (occasional long expeditions). Requirements typically Advanced certification or 15+ logged ocean dives.