The 4th Hole is the local name for a tiny inlet cut into the cliffs of The Coast Golf Club at Little Bay, between the tee and the green of the fourth, and it is one of the more unusual and rewarding small shore dives in Sydney. From the inlet the bottom drops to a clear area at about 8 m enclosed by rising rock walls. Following the eastern wall you pass a swim-through between a rock and a ledge; to the south is a cave system with a small swim-through behind the main cave; to the south-west a fine vertical ledge holds a three-metre-deep cavity that is always packed with eastern rock blackfish and luderick; and northwards there are more niches and another swim-through, with 12 m reached beyond the southern ledge.

Near the exit a long tunnel can be seen from inside but surge almost always makes it impassable. Port Jackson sharks and wobbegongs rest in the caves and, as at the neighbouring Little Bay, golf balls are the signature 'species'. The dive is small in area but dense in features and is noted as particularly good at night.

Its difficulty is entirely about the entry and exit: the inlet is narrow, high tide pushes a seaward current through it, and any real swell makes it dangerous, so it is a dive for experienced shore divers on a flat day, with a hard 50 bar reserve for getting out. The golf club bistro at the top of the fairway is the traditional debrief venue. It pairs naturally with the Little Bay beach dive for a two-dive morning on the same golf course.

Park in the rear car park of The Coast Golf Club off Anzac Parade at Little Bay (ask permission; the club is generally tolerant of divers). Walk about 100 m across the fairway of the 4th hole – wait for golfers to play through and watch for balls – to the small inlet between the tee and the green. Gear up on the rocks and enter from the inlet.

Exit via the same inlet, staying submerged until you are in half a metre of water, or via the gully to the left at low tide.

Only in slight seas with no waves breaking at the entry and exit points – the inlet is narrow and any swell over about 0.5–1 m turns it into a surge channel. At high tide the tidal flow creates a seaward current in the inlet and the exit is harder; at low tide the gully to the left provides an alternative exit. The long tunnel near the exit is almost always too surgy to swim through.

Westerly winds and flat seas, typically winter, are the conditions to wait for. Keep 50 bar for the exit.

Descend to the 8 m floor of the inlet mouth, follow the eastern wall past the swim-through, head south to the cave system with the small swim-through behind the main cave, check the 3 m deep cavity in the vertical ledge to the south-west, then work north for about five minutes past more niches and another swim-through before returning north-west to the inlet, keeping 50 bar in reserve.

No regular operator; experienced independent divers and St George Scuba Club.