Navy SEALs have endured a brutal crucible and are among the nation’s elite warriors. They are highly trained, incredibly fit, and instilled with an unshakable will to see the job done.

It makes sense that so many aspire to join their ranks. However, very few make the cut.

Related: How to get in shape like a Navy SEAL.

Before you can become one of America’s elite warriors, you first have to survive the Navy’s Basic Underwater Demolition and SEAL training, or BUD/S. The six-month course at the Naval Special Warfare Training Center in Coronado, California, has three phases designed to push prospective SEALs to their breaking point. With an attrition rate of 75 to 80%, it’s clearly effective.

So, how do you pass?

To answer this question, Task & Purpose turned to Stew Smith, a former Navy SEAL officer who has been writing on fitness for the last 17 years.

According to Smith, it starts with two things.

You need to be determined and mentally tough.

Students in Basic Underwater Demolition/SEAL class 279 participate in a surf passage exercise during the first phase of training at Naval Amphibious Base Coronado. Surf passage is one of many physically strenuous exercises that BUD/S class 279 will take part in during the seven weeks of first phase.
Surf passage is one of many physically strenuous exercises that BUD/S classes will take part in during the seven weeks of first phase.

“You really need to have some mental toughness about you,” Smith says, adding that mental toughness is what allows you keep going when you have nothing left.

“Never quit, and that’s the biggest thing,” he says. “Just don’t quit. And that’s tough, it’s easier said than done. They’re gonna keep pushing you, and you’ll make it through so long as you’re not quitting.”

You have to keep moving even when you don’t want to.

This means “finding the fuel, when the tank is empty,” says Smith. “Sometimes that is a near-daily experience going through SEAL training.”

However, Smith stresses that mental toughness isn’t enough by itself, you still have to meet the physical standards.

You need to be a lifelong athlete.

A U.S. Navy SEAL candidate swings to an elevated cargo net at a Naval Special Warfare elevated obstacle course, May 11.
A U.S. Navy SEAL candidate swings to an elevated cargo net at a Naval Special Warfare elevated obstacle course, May 11.

Smith describes this as having a background in athletics, whether that’s playing sports in high school and college, or just a history of athleticism. Smith describes this as having participated in team sports for four to six years in high school or college, or having history of being consistently athletic.

Next, you need to identify your weak and strong suits.

“Once you have that foundation, now you have to find your weaknesses and make those strong, because, I will tell you this, BUD/S will expose your weaknesses within about a week,” says Smith.

Next, you have to get used to being uncomfortable.

BUD/S candidates cover themselves in sand during surf passage on Naval Amphibious Base Coronado.
BUD/S candidates cover themselves in sand during surf passage on Naval Amphibious Base Coronado.

“You need to know what playing with pain is like,” says Smith. “One of my favorite terms is ‘getting comfortable being uncomfortable,’ because when you’re going through SEAL training you’re gonna be wet and sandy all day long.”

Smith says that eventually you’ll get so used to being wet, sandy, and uncomfortable that when you’re not, it feels strange.

“It’s one of those schools that makes you uncomfortable all day long,” says Smith. “That really all comes down to mental toughness and how much you can endure without letting it bother you.”

You need to cultivate the right mindset.

A BUD/S student lifts "Old Misery," a significantly larger log than other logs used in this evolution, during log physical training at the Naval Special Warfare Center at Naval Amphibious Base Coronado.
A BUD/S student lifts “Old Misery,” a significantly larger log than other logs used in this evolution, during log physical training at the Naval Special Warfare Center at Naval Amphibious Base Coronado.

“I’m a firm believer that it comes through a long period of time of persistence, it’s hard to just read a motivational quote and now you’re mentally tough,” says Smith. “It’s every day, waking up early when you’re nice and comfortable in your bed and it’s cold outside and you’re going to go for a run or hit that swim.”

By doing that, day after day to the point that it becomes not only easy, but a part of you, you’ll ready for the challenges ahead.

“That’s a hard one to coach because it’s not an immediate gratification quality,” said Smith adding that it takes commitment, determination, and persistence.

Lastly, there’s one thing you absolutely have to avoid during SEAL training.

You can never think about quitting.

A U.S. Navy SEAL candidate navigates a suspended cargo net at a Naval Special Warfare elevated obstacle course, May 11.
A U.S. Navy SEAL candidate navigates a suspended cargo net at a Naval Special Warfare elevated obstacle course, May 11.

“It’s a hard one to avoid, because it pops into your head, uncontrollably at times, but you cannot even think about quitting,” says Smith “It shouldn’t even be a thought in your brain.”

You can avoid doing that by being competitive, says Smith.

“If you really want to survive BUD/S, you can’t just survive it, you have to compete through it,” says Smith. “Whether it’s competing with yourself or competing with the guy next to you. Just having that competitive mindset can really keep your mind away from negative thoughts of quitting.”

In short, if you go into the training with an eye toward winning, giving up won’t cross your mind, or at least it won’t stick.

“If you go into that event competing, you never think about quitting,” says Smith.