Underworld Tulum

09/05/2026

Congratulations Eric for successfully competing Intro Cave with Shannon followed by heliotrox with Lanny. This was a demanding programme to level up your horizontal and vertical diving and you smashed it! Nice work buddy - it has been a pleasure to be part of your diving journey.

06/05/2026

Well done to our fellow Royal Navy veteran Peter on taking the first step on his diving journey to become an SSI open water diver. Lots of hard work resulted in a solid pass and we saw some cool stuff along the way. How many OW classes include swimming with a crocodile?!

30/04/2026

Congratulations to Ben on getting through a demanding SSI Overhead DPV class. All Underworld DPV classes involve use of a tow scooter on all overhead dives, multiple stages, oxygen deco and complex team failures a long way back in the cave. We managed to see some epic cave along the way, including a memorable 3 hour graduation dive to the Blue Abyss. This is a new SSI class and ours was one of the first to be run globally. The required 240 minutes of cave DPV time is a little more than some certs require, and we managed to triple it with over 800 minutes in the water.

26/04/2026

Cave DPV weeks are the best! We have had a great time scootering in spectacular caves and growing skills to deal with multiple complex failures. We try and make Underworld classes as realistic as possible, and this was no exception with multiple gas and DPV failures a long way back in the cave. Great work by Dylan and Ben meant that we made it back to the surface OK!

15/04/2026

DPV Cave Wednesdays! What are you doing today?!

11/04/2026

Cave Camp - The Final Reunion. 12-26 September 2026

Join us for 2 weeks of fun diving, presentations and socials. This is a friendlier and more low key event than the original full on Cave Camp events - a great chance for old friends to get together and enjoy some dives. Get in touch to book your space!

08/04/2026

This is the latest blog we have contributed to . It looks at a historical cavern diving event in which the guide and two divers lost their lives. When analysing things that went wrong, how many times have you heard something like “well they shouldn’t have used that gas, missed that jump, dived in marginal conditions”? This is where applying Human Factors and the new Learning From Emergent Outcomes LEODSI class differs from traditional incident analysis. Rather than judge decisions in hindsight and on severity, we ask: "How did this make sense to those involved?"

https://www.thehumandiver.com/post/chac-mool-triple-diving-fatality

Chac Mool's 2012 triple fatality wasn't caused by one bad decision. A LEODSI analysis reveals how organisational drift, depleted gas margins, and a system that punished safer choices combined to produce a preventable tragedy.

04/04/2026

It has been a busy couple of weeks at Underworld, with lots of guided diving, classes and fun dives. The highlight was definitely the SSI Full Cave Instructor Evaluation for our friend Bram Van Den Heuvel. We had some interesting dives with some simulated (and real) student issues, and Bram was the epitome of calmness and professionalism throughout. All our advanced training programmes, and especially instructor level classes, integrate HF principles from The Human Diver which really helps bring out the best in divers and instructors. Huge congratulations to Bram and a big thank you to Michael Bransfield, Scuba Claire and Gerry for helping out.

21/03/2026

This is a cool article in the always excellent InDEPTH Magazine about the forthcoming Human Factors in Diving Conference. https://indepthmag.com/human-factors-in-diving-conference-2026/ This is a great opportunity to get some fascinating insights from leading divers and educators and we can't wait to join the team in Croatia.

Human Factors in Diving Conference 2026 takes place in Vis, Croatia, from 31 May to 5 June, with practical sessions on diver safety, teamwork, and technology.