Trip Report: Tommy Grahams Cave 

By Joseph Bicanic

Tommy Grahams Cave has so much diversity to offer Cave Divers, which is why Tommy’s (as it is affectionately known) is one of my favourite Cave Diving Systems on the Nullarbor. In November of 2019, I ran a trip for six of us where we spent a week exploring the system, and for three of us it was our second visit to Tommy’s during the year. 

Getting there 

The drive from Perth takes around eleven to twelve hours to Cocklebiddy Roadhouse and then a further thirty minutes off the beaten track to arrive at the site. Some supplies can be purchased at Cocklebiddy Roadhouse (and the meals are quite good as well). However, the nearest regional center is Norseman, 435 km from Cocklebiddy and no, there is no Dive Strip. Bring everything, which for me includes a portable gas hot water system for the shower, a generator, 280 litres of water, a microwave and an air fryer for heating up the Cherry Strudel as well cooking a mean Rib Eye steak to perfection!

Upon arrival, the first job is set up camp and then get the gear to the mouth of the cave. Next is hauling in the gear. Tommy’s is one of the most laborious sites to haul gear to the water’s edge. Many a Cave Diver has vowed (swore / cursed) never to return, but most do. 

As some of the group arrived on different days, on haul in day there were only four of us on site. This meant hauling in gear for four people as well as running the air fill line from the compressor, located about 30 meters from the mouth of the cave, to the water’s edge (some 200 meters away from the compressor). 

Getting the gear to the water 

The path to the water’s edge is in two parts. In the first half we crawl, walk and clamber our way down through the dry cave starting with the first restriction, aptly named “The Birth Canal”. We play “Pass the Parcel” through the restrictions and then continue the game through the second part of the descent, down a fifty-five degree slope to the water’s edge. By the end of haul in day, no one wanted to dive. As inviting as the water was, we were shattered. Hauling in four sets of dive gear plus the fill line took six hours. To give some distance and height perspective, the entrance to Tommy’s is 90 meters above sea level, with the water table being at sea level. So each trip up or down is equal to climbing a 30 story building.

After a good night’s sleep, we were all ready for the cave and on that day we had an extra person, so five people took less than an hour to get one set of gear to the water’s edge. The walk up or down, when not hauling gear, takes twenty to thirty minutes depending on your fitness.

Diving time at last. Our group comprised of qualified Open and Closed Circuit Cave Divers as well as Open Circuit Cave Students. So, while some dived for fun, others were on the final dives of a combination TDI / CDAA Cave Course.

Diving conditions 

The water and dry cave temperatures are a toasty 24 degrees. This is notable as Tommy’s sits in the middle of seven other sites in a 32-kilometer radius and all these other sites are 19 degrees. With the temperature Being 24 degrees, a 5 mm wetsuit is sufficient, however, two members of our group on CCR were running Dry Suits.

On any Nullarbor trip, it is always advisable to check clothing, shoes, bedding, helmets etc. before use. One night, after my shower, I entered my camper trailer, went to put on my pants, then shat myself when I found a rather large eight legged furry and fanged guest that decided to make my pants it’s new home. 

What we saw

During the trip, we all managed to explore the two main chambers of the first sump (190 meters total distance separated by two parallel passages) as well as The Keyhole, The Five Ways, The Blue room (which has an amazing halocline), The Slot and several other unmarked holes. Parts of both The Slot and The Five Ways are dived side on, as the passages are quite narrow, but tall enough so that two divers can swim on their side, one above the other, so that the two divers are one to two meters difference in depth in the same section of cave during the dive. The map of the first sump has a recorded maximum depth of 30 meters; however, we found a few spots deeper and achieved a maximum depth of 36.4 meters not too far from the waters entrance.

The two divers clambered across the “Inner Sanctum” (an 80 meter dry chamber with a reasonably steep ascent and descent) that connects sumps one and two. The air here has a high levels of CO2, so the crossing must be done while breathing off your cylinders or CCR’s. Earlier this year, six of us did the crossing on Open Circuit. Breathing through a second stage while in scuba gear and carrying two cylinders is bloody hard work. 

To get sufficient gas, we often purged our regs during the trek. This trip, two of the same divers crossed the Inner Sanctum on rEvo CCR units. The work of breathing on CCR during the crossing was easier than Open Circuit on the previous trip. 

The second sump starts at Glacier Lake and has a distance of 130 meters, where there is another small dry chamber called The Terminal Rock Pile. There are some minor passages in the second sump, but one dive on CCR allows for it all to be explored easily. The Second Sump is a “nice” to visit rather than a “must” and is easily completed on rule of 1/3’s on twin 12 litre cylinders from the beginning of sump one. However, a minor problem in either the second sump or the Inner Sanctum could quickly turn into a major one. It is not an overly difficult trek, but like all caving and cave diving, the risk increases when help is further away. 

Haul Out 

With all course dives completed, the last dive of the trip saw three of us completing a 4-hour 15-minute CCR dive with a maximum decompression obligation of 15 minutes. Our maximum depth was 36 meters, but our average was only 18 meters.

The next and last day was haul out day, which again took six hours to complete (the air fill line was taken out the day before which saved time).  We then packed up camp, had a farewell Short Black coffee before the long drive back home.

I run Nullarbor Trips two or three times a year for a minimum of six and a maximum of 10 keen customers. August to April has the least amount of rain and irrespective of how hot or cold the days are, once in the cave, the temperature is a constant 23 degrees (19 degrees at all other sites). For more information on Nullarbor Trips go to or send an email to

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