U-Boat Worx C-Quester personal submarine
U-Boat Worx, a company based in the Netherlands, created the C-Quester submersibles for private and commercial users who require a small, easily operated submersible for pleasure or work related activites. U-Boat Worx designed the C-Quester as a one-atmosphere submersible. This means there is no pressurised atmosphere inside - it's the same as the atmosphere outside. Because of this the C-Quester can dive to its maximum depth of 50m (150 ft) and return again at the operators discresion, without the need for decompression. The time spent underwater is only limited by the life of the electrical power supply.
I don't know what occasion wouldn't call for the need of a personal submarine. Although if you tried to take this thing deep enough to be interesting you'd be squashed like a bug. And I'm not sure you want to be exploring the depths of the ocean in a vehicle that looks like it'd break if you leaned on it too hard.