Open it up and you’ll see a number of different items you might buy on the spot.
One item is aHorizontal-striped wet suitselling for 3,000 Bells.
Go over to the terminal inside Resident Services.

You’ll find theNook Inc. wet suitfor 800 Nook Miles.
How to Dive
check that that you have a wetsuit in your pockets.
Open up your pocket inventory and wear/equip the wetsuit.

It will go over all of your other clothing, which will go back into your pocket inventory.
Either way, enter the water by pressing theAbutton on your Nintendo Switch.
As you swim around, you’ll notice some areas where bubbles are coming up from underwater.

These are where you’re free to catch sea creatures like octopi and lobsters.
To actually catch these creatures, all you have to do is swim to those bubbles and pressYto dive.
Your villager will swim underwater and emerge with a sea creature in hand.
Along with donating sea creatures, you could also give them to a non-playable character named Pascal.