How the Navy SEALs Work

By: Lee Ann Obringer & Francisco Guzman  | 

SEAL Training: BUD/S

SEAL underwater training
Mass Communication Specialist 3rd Class Alex Perlman, left, assigned to Commander, Naval Special Warfare Command (NSWC), photographs U.S. Navy SEAL candidates participating in BUD/S training. U.S. Navy photo by Mass Communication Specialist 1st Class Sean Furey/Released

Now that you've passed the physical screening test, it's time for Basic Underwater Demolition/SEAL (BUD/S). This begins with a two-month training period at Naval Special Warfare Preparatory School in Great Lakes, Illinois.

Prep School ends with a modified physical screening test, by which time candidates have to be able to:


  • Swim 1,000 meters (3,280 feet) with fins in 20 minutes or under
  • Do at least 70 pushups in two minutes
  • Do at least 60 situps in two minutes
  • Do at least 10 pullups (no time limit)
  • Run 4 miles (6.4 kilometers) with shoes and pants in 31 minutes or under

Basic Underwater Demolition/SEAL (BUD/S) training is divided into several phases:

  1. Preparatory
  2. Orientation
  3. Basic conditioning
  4. Combat diving
  5. Land-warfare training

There is also the infamous Hell Week, which takes place toward the end of basic conditioning, which is the toughest training in the U.S. military. Hell Week is 5-1/2 days of difficult training on fewer than four hours of sleep. It's held in the first phase of BUD/S training, before the Navy makes an investment in SEAL operational training. More on Hell Week later in this article.

BUD/S lasts six months. The initial orientation comprises three weeks of learning the expectations and ways of Navy SEALs. More important, it is a time to prepare physically and mentally for what's ahead.

Once orientation is complete, the remaining time is broken down into seven weeks of basic conditioning, seven weeks of combat diving and seven weeks of land-warfare training. The training takes place at the Naval Amphibious Base at Coronado, California.