Boat Trailer Reef is an unpretentious reef dive just outside Terrigal Haven, and its name tells you most of the story: a boat trailer was dumped or lost here years ago and now sits on the reef as a handy landmark, encrusted with growth and sheltering small fish. The Terrigal Underwater Group lists the site at 24 m, about 500 m offshore from The Haven, and notes that the wreck of the SS Yambacoomba lies nearby, which gives the dive a bit of historical interest beyond the reef itself. The reef is typical of the inshore Terrigal area: low sandstone ledges, boulders and gutters running down to sand, with kelp on the shallower tops and sponges, sea squirts and small gorgonians on the vertical faces.

The trailer itself is the natural focus for photographers, since its frame and cross-members have become a mini artificial reef with encrusting growth, small blennies and gobies, and the occasional octopus or moray tucked into the gaps. Because it is so close to the ramp, the site is often used when conditions further out are marginal, as an easy second dive, or for Advanced and Deep training where instructors want 20 m-plus without a long boat ride. Fish life is what you would expect close to Terrigal: yellowtail and silver sweep over the reef, red morwong and blue groper around the ledges, wobbegongs on the sand edge, and seasonal cuttlefish.

Divers looking for the Yambacoomba should manage expectations - it was a wooden steamer lost in 1917 and what remains is low and scattered. Combined with the reef and trailer, though, it makes a varied, low-effort dive that shows how much life a scrap of hard structure attracts on an otherwise sandy seabed.

All boat dives in this area launch from the Terrigal Haven boat ramp at the southern end of Terrigal Beach, tucked behind The Skillion headland. From the Central Coast Highway follow Terrigal Drive into Terrigal, then Kurrawyba Avenue and Terrigal Esplanade to The Haven, where there is a paid car park beside the ramp; Pro Dive Central Coast's shop is a short walk away and gear is loaded on the ramp or the adjacent beach. Private boats need a ramp with good parking early on weekends as the car park fills by mid-morning in summer.

Boat Trailer Reef is the closest of the boat sites - about 500 m out from The Haven, a run of only two or three minutes around The Skillion. It is sometimes used as a check-out or second dive because of the short transit, and in very calm conditions private boats can reach it with minimal fuel and time.

Terrigal's offshore reefs are open to the Tasman Sea and are dived only when swell is below roughly 1.5 m; a north-east sea breeze building through the afternoon in summer and strong southerlies after a front are the usual reasons trips are cancelled, so morning departures are the norm. The Haven boat ramp is sheltered by The Skillion but the run out past the headland can be lumpy in a south-easterly. Visibility is best in late summer and autumn when the East Australian Current pushes warm blue water inshore, and worst after heavy rain when Terrigal Lagoon, Wamberal Lagoon and Avoca Lagoon open and stain the inshore water.

Winter water is cooler (around 15-17 °C) but often clear.

Descend to the reef, locate the boat trailer as a reference, then work the reef edge down toward the sand at 22-24 m. If conditions and time allow, swim out to look for the scattered Yambacoomba wreckage before returning along the reef to ascend on the anchor line or with an SMB.

Pro Dive Central Coast (Terrigal Haven) runs boat dives from The Haven most days, weather permitting; Central Coast Divers also runs Terrigal charters; the Terrigal Underwater Group dives the site from club and members' boats. It is usually offered as a second dive or when conditions or demand favour reef sites over the ex-HMAS Adelaide.