Leaving Oahu in a few hours after spending a week here. There are some great places to run. I did an early morning run from my hotel, around Diamondhead, then up to the top to watch the sunrise and back down to the hotel. Running Diamondhead road is great in the evening also. Downtown is tough with so many people in the way. As for swimming, I went to the pool on one of the military bases but you can swim at plenty of the beaches and it’s not hard to find somewhere without people all over. Have fun... I used to live here and this week really made me miss it.

Yeah Waikiki beach is shallow, calm, fairly long and empty in the morning. You can swim 20 yards off the beach parallel to the beach.

Lucky you, I’ve just left ... love it there.

We stayed in Honolulu and I ran most mornings. You can run from Waikiki on the boardwalk (I started near the Duke Statue) along the beach (lots of other runners but you’ll have plenty of space in the early morning) towards Diamond Head .. swimming, as already suggested, across Waikiki beach. The water is calm and shallow for quite some way. Also it is incredibly beautiful, clear and warm. The beach at Ala Moana is also very good. There’s a swim group - Waikiki Swim Club - that you can tee up with.

Enjoy

For pool swimming there is a City pool in the Manoa valley. 50 meters with minimal lane ropes check for lap swim times. Beautiful location, water sometimes is cold. Open water swim downtown/Waikiki either at Ala Moana Beach Park. Sort of a ditch but they have a marked off course. The beach right at the start of the Roughwater swim is next to the old Natatorium/WWI memorial just Diamond Head direction from the Aquarium.

Pretty nice run is from Waikiki Beach around Diamond Head and back. If you like trail running Tantalus/Roundtop Road is full of trails. Fairly flat if you start at the top , or a giant hillclimb if you start at the bottom. The HURT 100 miler uses these trails. Dropdead beautiful is the Manoa Cliff Trail. at the top. Some people like to run up the Koko Head stairs as well. Starts out in Hawaii Kai. Those are all worth doing.

Now if you want a run/ swim combo try Waimanolo Beach on the East side. Be sure and lock the car up, small kine Hawaiian borrowing going on out there. Or Kailua Beach Park you can swim/run there too, or Ala Moana Beach park has a running beach/park there as well.

How about cycling ? Any safe routes?

Depends what you call safe. Probably 90% of the town side riders leave Waikiki down Kahala Ave, left at the golf course, right at Kahala mall out to Hawaii Kai, up Hanauma Bay hill, to Rabbit Island turn out, on to Waimanalo. There are some country roads if you turn left at the 1st 7-11 store you see in Waimanalo. That will add a few miles to your route. Doable to go thru Waimanalo on the main road, but I think it of being sketchy. Much safer in the valleys roads.
The Tantalus/Roundtop loop is pretty safe and very scenic. About a 5 mile climb either way.

Thanks

Run around Diamond Head early morning or evening.
Sprint workouts on the grass at Kapiolani Park.
Swim out to the Flag and back a few times at Kaimana Beach or get with the local swim group and do the rough water loop.
Ala Moana park is also good for a long swim set.

If you're in town/Waikiki, these are the most popular options. Cycling in the heart of Honolulu has gotten a lot better in the last 3-4 years, but it's still more of a means to safely get out of the city. Once out of town, you have a lot more options to mix things up. You can go all the way out to Waimanalo and beyond, or you can turn around at Hawaii Kai and ride up all the residential climbs on the way back to town. They are short and nasty...usually around 1.5-2.5 miles at an average of 8%, with lots of sections above 12%.

Tantalus is a much longer and more mellow climb and is pretty steady at 5-7%. A lot more narrow, but very few cars.

Another popular route is to ride over the Pali Highway and loop back around East. I would suggest doing it with a guide or a local group though as there are certain sections that can be sketchy. Lots of riders do it all the time, but you just have to know where you need to take the lane and where you need to hug the shoulders.