You must have one of the following ratings before entering BUD/S:

Aviation Boatswain's Mate Equipment (ABE)

Aviation Ordnance man (AO)

Boatswain's Mate (BM)

Electrician's Mate (EM)

Engine man (EN)

Electronics Technician (ET)

Fireman / Fireman Apprentice (FN/FA)

Gunner's Mate (Guns / Missiles) (GMG/GMM)

Hospital Corpsman (HM)

Hull Technician (HT)

Interior Communications Technician (IC)

Intelligence Specialist (IS)

Machinist's Mate (MM)

Machinery Repairman (MR)

Operations Specialist (OS)

Photographer's Mate (PH)

Personnel man (PN)

Parachute Rigger (PR)

Quartermaster (QM)

Radioman (RM)

Seaman / Seaman Apprentice (SN/SA)

Storekeeper (SK)

Signalman (SM)

Sonar Technician [Surface] (STG)

Torpedo man (TM)