The HNL Marathon is an incredible experience! A marathon through the beautiful city of Honolulu is a perfect way to end the year.

Race registration starts 11 months in advance. Register early to get the best pricing.

The expo is moderately-small. It includes a lot of vendors that aren't even running-related, which was a bit odd. Bib pick-up was quick, and I was a little annoyed that they were not checking identification as promised. This is important for a majority of the running community, especially after we were told in emails constantly that ID would be checked.
You also pick up your gear check bag, which you would need to drop off the day before the race if you were to use it-- the start and finish lines are not in close proximity, so they transport them in advance. It makes sense to me, though I've seen other runners complain about this.
I was impressed with the huge variety of official race merchandise. There was literally anything thing you could think of branded with the race name on it!

Day of the race, I was staying in a hotel near the finish, so I took one of the shuttles to the start line. That was really quick and efficient! The start area is easily the biggest opportunity for improvement. There was no security, which I think should be in place for a race of this size. There were no seeded start corrals. With almost 25,000 runners, you simply cannot get away with not organizing the runners by expected finish time. I'll be honest, I was really frustrated by this. No matter where you squeezed up to, this made it really difficult to avoid walkers in the first 400 meters even(!). This alone makes this course not a PR course. I spent the first mile weaving and I was pretty far up.
Once you begin, the course winds through some of the downtown area before heading down to Waikiki, which was beautiful! The course then heads up High-Five Hill around Diamond Head, which was just so awesome. Countless volunteers every few paces for more than a mile just there to give high-fives and cheers of positive energy.
The course eventually winds to a highway, where most of the race is on. This part seemed to last forever. There are some pretty views along this out-and-back stretch, but I have to say it is still quite boring. I wish the course took you on some more "local" streets and neighborhoods just to mix it up and keep it from feeling too monotonous. On the way back in, I remember feeling beyond relieved I was done with the highway portion. Finally, you end in a park right near the beach to a beautiful shell lei and a gigantic and wonderfully designed medal!
Aid stations were plentiful, but a few more couldn't hurt, especially with how hot and humid Hawaii weather tends to be. Not all aid stations had water and Gatorade, and they weren't always in the same order. It was quite confusing at times. As other runners have pointed out, the Gatorade was incredibly watered down to the point that it was almost not worth it. I was really disappointed in that. Some aid stations also had ice cold sponges, which was always a treat to see! One aid station in the last third also had a few GU flavor options, which I happily accepted.

Overall, I would do this race again. I was running this race just for the experience, not to PR. I ran an overall good race, but did need to increase my hydration to adjust a bit, but that is to be expected. The views and spectators make this race worthwhile. It's Hawaii, after all!!