u/Equivalent_Net_1502

I’m currently in a 4-player level 5 campaign. In our last session, we learned that there’s a box full of adamantine at the bottom of the deep ocean, weighing around 30,000 pounds total. We want to retrieve it, but for certain reasons we have to do everything in a single trip within one day (it's really hurried).

Are there any spells or strategies that would let us dive down and recover the adamantine without specialized equipment?