Tenements 1, known to the dive team as T1, is one of a pair of connected sites on Heron Reef. The mooring sits in 12 m on bright white sand, and from there gutters lead to a small wall that is teeming with sea life, with deeper bommies beyond reaching about 16 m. Its moderate depth and simple layout make it suitable for all levels.

Silver drummer, red bass and fusiliers school in the shallower areas, while the wall is decorated with large anemones hosting anemonefish, making it one of the better photo opportunities on the reef. Around the deeper bommies, porcupinefish and flutemouths are common, and the site sees the passing grey reef sharks, barracuda and mackerel that make the adjacent Tenements 2 famous. T1 is often the finishing point of a drift from Tenements 2, since the incoming tide carries divers from T2 towards T1.

On its own it can be dived as a stationary dive from the mooring. The resort lists 'Tenements' among its top ten sites. The site suits new divers who want a wall dive at friendly depths, and photographers looking for anemone and schooling-fish images.

Because the current can run here, listen to the briefing about which way the dive will go. The earlier database pass combined Tenements 1 and 2 in one row; they are now separate, following the dive operator's own listing. A 'Tenements 3' mentioned in some lists could not be verified from published sources.

The white sand around the mooring reflects a lot of light, so even on overcast days the shallow gutters are bright, which helps when photographing the schooling drummer and bass.

Heron Island is 72 km north-east of Gladstone. Fly or drive to Gladstone, then take the Heron Islander ferry from the Gladstone Marina terminal (72 Bryan Jordan Drive; check-in from 7:45 am, departs 9:30 am on scheduled days, about 2 hours), or transfer by seaplane or helicopter. Dive gear is carried on the ferry in addition to baggage.

On the island, the dive centre sits beside the harbour; boats leave the jetty for three dives daily and most Heron Reef sites are 5-15 minutes away. Tenements 1 is about 10-15 minutes from the jetty along the reef edge, dived from a mooring in 12 m.

Heron Reef sites are chosen on the day by wind and tide. The prevailing south-east trade winds (strongest April-September, often 15-25 knots) make the southern and south-eastern reef edge rough, so the sheltered northern and western sites are dived most. Northerly winds in spring and summer reverse this.

The tidal range is up to 3-4 m and currents run strongly around the reef edge and through Wistari Channel on springs; visibility is usually best on the incoming tide. Cyclone season is November-April; summer storms and plankton blooms can drop visibility to 10 m. Stingers are uncommon this far south but present in summer.

The Tenements are affected by tidal flow: on the incoming tide divers drift from Tenements 2 towards Tenements 1, so the dives are timed accordingly.

Descend the mooring to the white sand at 12 m, follow the gutters to the small wall and work along it looking at the anemones, then drop to the deeper bommies at 15-16 m. Return along the top of the wall and gutters to the mooring for the safety stop.

Heron Island Resort Dive Centre is the only operator: three guided boat dives a day (about 9 am, 11 am and 3 pm) plus scheduled night dives, from the resort jetty; sites are rotated by tide and wind. Access requires a stay at Heron Island Resort (or the University of Queensland research station). Tenements 1 and 2 are often dived as a connected drift.