I would think the waves at Hapuna would be fine for a beginning boogie boarder. :)
Here is a list I made a while back about the Big Island. (I used to live there; now I live on Kauai.) The pages I quote are from Big Island Revealed, 3rd edition.
Activities
1. Kayak across Kealakekua Bay - we rented our kayak from Kona Boys
(808-328-1234) and they were great!
2. Hike out to flowing lava - drive down Chain of Craters Road (in
Volcanoes National Park) to the end and hike out to where the current flow
is. If you want to call ahead, the number is 808-985-6000. They have a
pre-recorded update as to where the lava is flowing. I highly recommend
staying in Hilo overnight or at a B&B in Volcano Village if you decide to go
to the volcano. It will give you the chance to really explore the park and
you won't have to drive ALL THE WAY back to Kona in the same day! Very
relaxing. Volcano Village is a great place. Aloha Junction
(www.bbvolcano.com) is a nice little inexpensive B&B we enjoyed. They have a
jacuzzi -- there is nothing like soaking in a hot jacuzzi in the mist after
a night of walking around on the lava!
3. Walk to a secluded waterfall - if you have Big Island Revealed (3rd
edition), check out pages 228-229. That's all I need to say except this:
TAKE INSECT REPELLENT! We loved this hike and would do it again (it's more
of a wet walk than a hike), but we got chewed big time by the mosquitoes! Be
prepared and be smarter than we were -- you'll LOVE this! It's amazing and
we never saw another soul the whole time we were out there.
4. Place of Refuge (Pu'uhonua O Honaunau) south of Kailua-Kona - page 71
in Big Island Revealed. Very pretty, very Hawaiian place. Important and
interesting.
5. Waterfalls of the Hamakua Coast - Rainbow Falls (you can drive right up
to it), Akaka Falls, Uma Uma Falls, and Kahuna Falls. All are well worth
getting to! I think the best time to see all of these falls is in the
morning when the sun is right. Morning is prettiest in Hilo and these falls
are all on the Hilo side. Be sure to look out (if you're not the person
driving!) for the little unmarked waterfalls along the side of the road as
you drive down the Hamakua Coast!
6. Beaches - Mauna Kea Beach (Kauna'oa), Hapuna Beach, and Kua Bay are my
favorites. Kona Coast State Park (Kekaha Kai) is also really nice, but you
need 4WD to get to it. Really rocky road in! Make sure you spend AT LEAST
one day hanging out and enjoying the sun. Use sunscreen! :) The Hawaiian
sun will fry you in minutes if you're not careful. Kahalu'u Beach right in
Kailua-Kona is a good beach for snorkeling. You can rent snorkel gear for about
$9/week at Snorkel Bob's in Kailua-Kona (right near Huggo's restaurant on
Ali'i Drive).
7. Punalu'u Black Sand Beach - You can drive right up to the black sand!
Very cool. Lots of green sea turtles (protected in Hawaii, endangered
species) there. Some will rest right on the beach and you can take pictures! Just don’t get too close. Respect their space or people will report you. Trust me on this! (I’ve reprimanded people myself for harrassing the turtles.)
The water is beautiful and really cold in lots of spots. It is fed by fresh
water somehow and that makes it cold. Great place to spend some time hanging
out on the way to the volcano.
8. Green Sand Beach - page 173 in Big Island Revealed. Either hike or
drive out in a 4WD vehicle. Don't take any of the sand either here or at
Punalu'u (or anywhere else, really). :) The green and black sand in
particular are finite and if everyone takes just a little, there won't be
any left in a few years. Sorry for the lecture, but I get so steamed when I
see people filling up little vials (or big bags!) with green and black sand!
9. Ahalanui - page 117 in Big Island Revealed. Don't miss this if you can
help it! Really, really neat ocean water hot spring to swim in. Off the
beaten path and like nothing you've ever seen before (probably)! The water is warm because it’s heated by lava. Pretty neat!
10. Pacific Tsunami Museum - Nice little museum focusing on the 1946 and
1960 tsunamis that devastated Hilo. Inexpensive, very informative, and
interesting. Only about $5 to get in. Closed Sundays.
11. Kalapana - This is the name of the town that was overrun by lava in
1990. Page 119 in Big Island Revealed. Not much to see there, but it's
interesting and there’s a little snack stand that sells hot dogs and stuff there.
12. Kaumana Cave - page 146 in Big Island Revealed. This is a nice little
lava tube that you can walk into just a few feet off the Saddle Road. If you
don't want to drive the Saddle (it's not that bad a road but the rental car
companies don't want you driving it), you can come in just a couple of miles
off the Hilo side and find the cave from there. It's very damp and pretty.
We took our Christmas card picture there in 2000!
Restaurants, etc.
1. Tex Drive Inn in Honoka'a (on the way to Hilo) - they make the best
fresh malasadas! They're a Portuguese donut without a hole and they're
delicious! There's nothing like sitting on the lanai at Tex when it's
raining on the roof and you're eating a malasada and drinking a cup of
coffee. Ahhhh...
2. Huggo's on the Rocks on Ali'i Drive in Kailua-Kona - This is the place
next door to Huggo's. On the Rocks is a little bar-type place situated right
on the sand. The view is great and at night they have live music and hula.
The service is usually slow and even sometimes rude, but just enjoy the
pupus (appetizers) and the view and you won't care!
3. Kona Brewing Company (Brewpub) in Kailua-Kona - great locally made
beers and terrific pizza! Not near the beach, but
nice atmosphere anyway. The Kohala pizza is great and I LOVE the roasted garlic appetizer!
4. Ken's House of Pancakes in Hilo - If you're over that way, it's worth a
stop. Ken's is open 24 hours, which on the Big Island is a rarity. Their
menu is huge and the waitresses are almost all old-timers. Good local grinds
(food) at good prices. Fun atmosphere; very 'local.'
5. Punalu'u Bakeshop in Na'alehu (south island, on the way to the
volcano) - really yummy taro and guava bread -- and cool T-shirts that state
it's the "southernmost bakery in the U.S.! -- as well as mac nut ice cream
sandwiches dipped in chocolate!
6. Roy's (in Waikoloa) - upscale Pacific Rim food. Roy's is a chain and
they're all throughout the islands as well as on the mainland. I LOVE Roy's
food and the chocolate souffle is to die for! Well worth a drive up to
Waikoloa...and you can shop at the King's Shops afterward!
7. Kona Mix Plate - local style fast food. Try the loco moco or even SPAM
musubi! My son loves it. Best thing is to grab a plate lunch and go out
to the beach for sunset. Very relaxing and local type thing to do.
8. Java on the Rock - same location as Huggo's on the Rocks but Java on
the Rock is just for breakfast. Their fruit plate is great -- you HAVE to
try rambutan! It's a freaky little hairy fruit that is just delicious! Good
coffee and pastries and the view is incredibly clear in the morning. We ate
breakfast here almost every day on our trip in 2002.
9. Shave ice - Scandinavian Shave Ice on Ali'i Drive is pretty good. My favorite is li hing mui (like a really sweet plum flavor) with
soft serve ice cream in the bottom! Delicious. Try it with azuki beans too.