Her obituary’s already written. Bethany Hamilton will always be “the surfer who lost an arm to a shark, and got back on the board.”

But her story didn’t end when she did that, losing that left arm to a tiger shark in Hawaii in 2003. It didn’t so much as pause when she got back in the water seemingly overnight. It didn’t conclude with a flourish, when her guts and joy for the sport were celebrated in “Soul Surfer,” a warm and winning faith-based drama about her triumph against the odds.

“Bethany Hamilton: Unstoppable” picks up the story since then, a classic surf documentary with lots of waves, curls and rides coupled with the personal story of a professional surfer, struggling to compete, but already “one of the most famous surfers on the planet” thanks to what that shark did, and how she responded.

Using old home movies and years of following Hamilton, interviewing family and her peers, surf doc director Aaron Lieber paints a glossy portrait of a woman who’s multi-tasked her way through “The Amazing Race,” pro-surfing competitions the world over, marriage and motherhood to become an inspiration to a generation and an icon of her sport.

There is dazzling in-the-water/under-the-water footage, plenty of competitions to choose from, lots of hard training and physical therapy just to get her back up on that board and into the surf where the waves are.

Think about it. How would YOU lie on your belly and paddle out, through towering waves, to get to the launch zone — with one arm?

A telling home movie moment from her past came in the hospital after the shark attack. She was surfing with her just-as-blonde best bud Alana Blanchard, a future pro — both of them just 13 on that day in 2003 when the shark struck.

“I would just rather it be me than Alana, because I love her so much.”

There’s also pre-attack footage of the girls chatting with Bethany’s mother Cheri about sharks, what precautions they take — “Just pray.”

Both were traumatized, with Blanchard confessing “I would have nightmares” after the attack. Hamilton, near tears a few times in the hospital, would have the greater trauma to overcome. She did.

Truth be told, “Unstoppable” doesn’t do much that a hundred other surfing docs haven’t done — sometimes better — visually. It’s the personal story that has to sell it.

I interviewed Hamilton when she toured plugging “Soul Surfer,” and here she is, all these years later — still with a passion for the sport, still sporting that nasal surfer-girl vocal fry as she recalls “gnarly days” which still “felt so crazy-good.”

The film’s relentlessly upbeat take on her life has room for a few tears, when she’s battered and her chin bloodied after a wipeout, struggling to get back in form.

We meet her husband, Adam Dirks, and recognize the potential strain in the dynamics of that relationship, his “jumping on the Bethany bandwagon,” even if the filmmaker and his subjects don’t bring it up.

Her casual, “not ready for that” take on her pregnancy may be refreshing. But as she continues to compete through it, nursing her baby on the beach in between surfing heats, the viewer might wonder, “Who is keeping to whose schedule” — mother or son?”

This “I can have it all” ethos is underscored by the adjustments to her life she had to make, much the same as the adjustments she had to make to her surfing. Working/competing moms have to be super-organized. Check out the time-lapse of her elaborate packing routine for a big competition.

We see snippets of Bethany the celebrity — doing a cooking show, “The Amazing Race” and other sports-reality programming, and remember that she turned down an Espy (ESPN award) for “best athlete with a disability” because she didn’t like the label.

And then we see the competitions, with TV anchors saying her participation is “bigger than sports” and commentators at the competitions calling her “one of the most famous surfers on the planet.”

As surfing is judged subjectively, not unlike gymnastics, you’re allowed to wonder, as good as she is, if her fame and struggle aren’t giving her an edge with the judges.

Still, we’ve seen, beginning of the film to the end, that she’s still got the talent and drive, and she’s made her skills adapt to keep herself in the mix among the best in the world.

And if you can appreciate the irony, in “Unstoppable’s” opening moments, of Bethany Hamilton taking on the legendarily tough North Shore of Maui wave at Peʻahi, which surfers nicknamed “Jaws,” you can bet Hamilton has, too.

If a shark couldn’t stop her, no nickname, no menacing surf that is “mesmerizing, the most beautiful wave to see in person — but big, scary” was going to stop her either.

MPAA Rating: PG (for some thematic elements)

Cast: Bethany Hamilton, Adam Dirks, Kelly Slater, Timmy Hamilton, Cheri Hamilton, Shane Dorian, Thomas Hamilton, Noah Hamilton, Alana Blanchard, Coco Ho, Carissa Moore

Credits: Directed by Aaron Lieber, script by Aaron Lieber and Carol Martori. An Entertainment Studios release.

Running time: 1:38