Renting motorcycles

[JMartin]

There are some rental services that have helmets available, but I can't speak for Hawaii... you'll need to talk with the company there. But it's not unheard of.
Even the private-party bike that I once rented made the offer of some riding gear.

[stroguy]

Craigslist Hawaii

[blackmetoc]

Craigslist Hawaii

Good point.

[stroguy]

I took a quick gander and there were lots of em. Don't know where yo are in HI, but they are out there and cheap. When you get done with it drop it off at Goodwill or a pawn shop.

[ReserveBum]

if you are renting from Eagle Rider they usually have helmets to rent

[copper]

...helmets were not required.

[3Chief]

...helmets were not required.

The State of Hawaii may not require a helmet, however the DoD does have specific requirements when riding on/off their bases. Generally they require the following:

1) Helmet
2) Long sleeves
3) Long Pants
4) Boots with a defined heel
5) MC Endorsement on a valid License
6) MC Insurance
7) Eye protection, either a helmet visor or glasses
8) Closed finger gloves
9) If you are a member of the armed forces they generally require you to have taken that bases MC safety course if your stationed there.

Those are the general ones, each base will have other requirements depending on the CO. These requirements change periodically, I know that where I work they changed 4 times in three years. Generally if you meet these requirements and have base access you will be allowed on. Sometimes you will run into that guard who has an issue with bikes and can ruin your day. I had one that I finally filed a formal complaint on to stop the harassment. Some bases have requirements that are subjective....

[blackmetoc]

...helmets were not required.

Military regs requires I wear them, and to be honest, I've never ridden w/o one, short of moving the bike down to the wash pit.