| FROGMAN | Diver trained for underwater operations (7) |
| SUBMISSIONS | Proposals for underwater operations (11) |
| MINISUB | Vessel for up to two persons for underwater work (7) |
| SNORKEL | Tube for underwater swimming with mask and fins; or, a similar device for offroading through water in a 4x4 (7) |
| CAISSON | Structure for underwater construction |
| OARFISH | Idiotic, that's about right for underwater creature (3,4) |
| COURSER | A swift charger, steed or warhorse; a runner; a beagler or other hare hunter; a hound, trained for said chase; or, a plover-like bird, adapted for sprinting, rather than flying (7) |
| REPRINT | Sprinter, heading off, trained for later run (7) |
| ATHLETE | Who is trained for track and field events (7) |
| OFTENER | Trained for NEET more regularly (7) |
| TRADEIN | Trained for craft, contribute to deal (5,2) |
| NOMINAL | Lion man trained for virtually nothing |
| TROTTER | Horse trained for harness racing |
| DRILLED | Trained for a march-past |
| MILITIA | A body of citizens enrolled and trained for military purposes in time of emergency |
| MARINES | Body of troops trained for service at sea, on land, in charge of Naval affairs |
| DEPTH | Would diver order this for underwater attack? (5,6) |
| CHARGE | Would diver order this for underwater attack? (5,6) |
| ROV | Acronym for a drone-like robotic unit used for underwater research |
| SONAR | System for underwater detection of objects |
