Outer Doughboy, part of the St Helens Rocks system, is rated 8 out of 10 by the Marine Life Network guide. Its seaward face is a sheer rock wall to about 25 m, with invertebrates, crayfish and healthy fish populations including butterfly perch, wrasse and long-snouted boarfish.

The guide warns that the site is very exposed, that a current is present and that an experienced boat handler is needed. As with other St Helens sites, urchin damage was noted. The wall format suits a drift, with the boat following divers' bubbles.

It is a dive for experienced divers who can manage current and a live pick-up in open water.

The north-east coast from St Helens to the Bay of Fires is built of the same orange-lichen granite as Freycinet, and under water it forms rounded boulders, cracks and swim-throughs. The regional guide notes damage from the long-spined black sea urchin (Centrostephanus rodgersii) on several sites; this urchin has spread south with the warming East Australian Current and grazes kelp and weed down to bare 'barrens', so expect patches of bare rock among the weed.

The north-east sees far fewer divers than Bicheno or the Tasman Peninsula. There is no regular charter boat, so most diving is done by Launceston club members and visitors towing their own boats, and conditions are checked on the morning rather than booked in advance. The nearest hyperbaric chamber is the Royal Hobart Hospital, more than three hours' drive away; Launceston General Hospital has no chamber, so evacuation planning and oxygen on board matter here.

St Helens is on the Tasman Highway (A3), about 2 hr (165 km) east of Launceston and 3 hr 15 min from Hobart. Boats launch inside Georges Bay (St Helens town ramps or the St Helens Point ramp) or at Binalong Bay. The Georges Bay bar can be dangerous in easterly swell and on an ebbing tide; check MAST advice and cross only in good conditions.

Outer Doughboy is reached from the St Helens Point ramp across the bar, about 15-20 minutes. The regional guide stresses that an experienced boat handler is needed.

The St Helens and Bay of Fires coast faces east and north-east into the Tasman Sea, so easterly and north-easterly swell over about 1.5 m, and the common summer NE sea breeze, make it rough; the Georges Bay bar breaks in easterly swell. Westerly and south-westerly winds blow offshore and give the flattest seas and clearest water. Southerly swell wraps around St Helens Point.

Visibility falls after rain when Georges Bay drains tannin-stained water on the ebb. Very exposed; dive only in westerly weather with small swell. A current is often present.

Drop at the top of the seaward wall, descend to 20-25 m and swim along the face with the current, surfacing on an SMB for live pick-up. Turn the dive at half gas (thirds where current or overhead sections are involved), deploy an SMB before surfacing for the live-boat pick-up, and complete a 3-minute safety stop at about 5 m where depth allows.

East Coast Scuba Centre (124 Binalong Bay Road, St Helens) is listed by Wikivoyage as offering dive and snorkel equipment hire - current trading status and whether it runs boat dives are unconfirmed. Otherwise sites are dived from private boats and by Launceston clubs and Tasmanian Divers (Launceston) on occasional trips.