From the carpark off Coral Street, there are two entry points: the stairs at the western end of the carpark, or the beach just east of the carpark.
The best diving is along the sea wall stretching from the front of Jack Evans Harbour to the small beach on the northern edge of the river mouth. The seawall here is comprised of large boulders down to about 10m and hides a variety of shrimp, crabs, moray eels, and octopus.
You can also find juvenile lobsters on this section of seawall, a unique and surprising attraction of the Tweed River dive. The larger boulders at the bottom of the seawall are piled and lean against each other to create overhangs and miniature caves. To find juvenile lobsters look for pairs of one inch, bright white antenna sticking out of holes in the underside of overhead rocks.
The northern seawall is the outside edge of a bend in the Tweed River, and as such the water has scoured the sand away from some interesting rock platforms and low reefs. These are focal points for schooling silvers (blackfish, bream, tailor, whiting, dart) and provide a good mid current anchor point to hold onto.
This area is a great night dive site, and is one of very few sites in NSW where you can see river prawns amongst the rocks after dark.
Cross to the shallower sandy area on the southern, inside edge of the Tweed River to find spotted eagle rays, blue spotted rays, bull rays and flathead, but be aware that the current is stronger on the inside edge of the river bend.
Continuing up-river past Jack Evans Harbour will eventually take you past to the Hospital. The wall along here is comprised of smaller and looser rocks, with much less marine life. There are still silvers, flatheads and the occasional ray to be found, but not in the same quantities. The main attraction of this latter section is hunting for old bottles deposited on the river bend.
It is also possible, but not advisable without properly planning gas consumption and logistics, to reach the beach at Ebenezer Park where you can sit on the bottom in 4m and watch from below as Herons plunge into the water hunting fish.
To get the clearest visibility plan to dive around an incoming high tide when the cleaner sea water is dominant over the murkier river water. Smaller tidal changes will correspond with slower current and longer slack tides. Slack tide on the river is 30 to 60 minutes after the posted time tides for Tweed Heads.
Divers and fishermen share this area, so be courteous and try your best to stay out of their way. There is also a large volume of boat traffic over the site, so avoid any mid water ascents. It is also recommended that divers carry an SMB and know how to deploy it from at least 5m depth.