Some people like to spend their entire vacation lounging in the sun and feeling completely relaxed. Others, however, want a little bit more of a thrill out of their time away from the real world. If you're in the latter camp, you can find plenty of exciting activities on Oahu. Whether you're looking for a tiny rush, or you're ready to have your heart racing in your chest, you can do it. Head out of your Oahu vacation home and into one of these extreme adventures:

1. Rock climbing

Oahu is known for being Hawaii's best island for rock climbers, so there are tons of routes to choose from for every style and skill level out there. If you're a fan of rope climbing, you can head to the Mokuleia Wall. This wall has plenty of different routes, though many of them are more on the difficult side. If you'd rather try your hand at bouldering (unroped climbing that uses a crash mat for safety) you can head to Waimea Bay Bouldering. This rock face has plenty of paths upward, many of which are perfectly suitable for beginners. In addition, the sandy surface below means you don't necessarily need a crash mat – though you may want to bring one for extra security.

Not ready to try your hand at climbing outdoors? Head to the Volcanic Rock Gym. There you can practice climbing with the security of large, soft mats beneath you and clear and understandable routes. If you've never climbed before, it could be a good idea to visit the gym before you go to any of the outdoor locations, regardless of your current fitness level. This will help you get a feel for how to make your way up the wall once you're outside.

2. Mountain biking

Because Oahu has so much gorgeous natural terrain, it only makes sense that there would be plenty of wonderful trails for mountain bikers. Whether you're looking for a leisurely ride along the coastline or hoping to blaze through Oahu's forests, you'll be able to find something that's just your speed. For beginners or people who aren't looking for too hard a challenge, there's the Kaiwi State Scenic Shoreline trail. This has over 20 miles of ridable path, and it's all fairly easy terrain to deal with.

Be sure to use appropriate safety gear so you don't get hurt if you fall. Be sure to use appropriate safety gear so you don't get hurt if you fall.

If you're looking for a little bit of a challenge, you can check out the Pupukea trail. This route is also more than 20 miles long, though it's a bit rougher and features more climbs and descents than the Kaiwi trail. Finally, serious thrill seekers should ride the Peacock Kealia Loop. This is both exciting and challenging, as it has a difficult climb followed by a serious downhill run.

3. Skydiving

Anyone who has even a passing interest in skydiving should give it a shot on Oahu. After all, there's no view of the islands quite as spectacular as the one you'll find soaring downward at 120 miles per hour after reaching a height of 8,000-14,000 feet. If it's your first time jumping, no worries – the skydiving companies in Hawaii have trained divers ready to lead you on a tandem jump. They start the descent and pull the cords – all you have to do is enjoy the ride! 

4. Doors-off helicopter tours

If you'd like to get that high-up view of Oahu without plummeting to the ground, consider going on a helicopter tour. The most thrilling ones are doors-off, meaning you're experiencing all the fun of feeling the air rush past as you gaze on the ground below without having to ever leave the vehicle. You'll get a headset so you can communicate with your fellow tour-goers, as it gets pretty loud up in the chopper. This is an enjoyable and relatively low-anxiety way to see Oahu from far above. Bring your camera, or you'll regret missing the chance to catch an amazing shot. 

5. Swimming with sharks

In the last few years, there have been plenty of efforts to highlight the fact that sharks are fairly misunderstood creatures. Despite their ravenous reputation, sharks rarely attack humans on purpose. Most of the time if a shark attacks someone, its because it thought the person was a turtle or some other form of prey. If you want to see how truly un-scary these animals are, you can go on a shark dive. There are two kinds of dives: caged and open.

Have you ever wanted to meet a shark?Have you ever wanted to meet a shark?

You've probably seen footage of cage dives before – divers are secure behind metal bars, and the sharks swim around them. Open dives, however, have you swimming right next to the animals themselves. This may sound unwise, but with a trained instructor, it becomes a thrilling chance to see nature up close.