Deepest diving tank (and deepest pool)

Last updated: April 2, 2020 at 4:02 am

40 m (131 ft) — Y-40 located at the Hotel Terme Millepini, in Italy. Volume: 4,300,000 litres (1,135,939 gallons) of chemical-free thermal water kept at a constant temperature of approximately 33°C (91°F). The pool includes platforms, caves and a transparent tunnel for pedestrians. The pool was officially opened on June 5, 2014. The letter “Y” stands for the pool’s vertical axis while “40” is its depth.


33 m (108.27 ft) — NEMO 33 located in Brussels, Belgium. Volume: 2,500,000 litres (660,286 gallons) of drinkable (non-chlorinated) spring water. The pool includes levels at various depths, air pockets, simulated cave, 12 portholes, and temperature of 33°C (91°F).

15 m (50 ft) — The Bassin de plongée sous-marine du Parc olympique (Olympic Stadium Diving Pool) located in Montréal, Québec, was the largest dedicated — and public — diving tank in North America when it was inaugurated in 1976. It is currently closed and a decision on its renovation is pending. Volume: 1,800,000 litres (475,000 gallons) of chlorinated water. The 10 m x 14 m (33 ft x 46 ft) pool that includes three levels is kept at a constant temperature of 30°C (86°F).

Y-40 Hotel Terme Millepini

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