Just got my results: UNsucessful

What are the best days for a walk up permit?

There is a daily lottery two days before the hike date, and there is no walk-up permit process that I know of. Although when I stood in line for a walk-up overnight permit, there were several people looking to pick up one of those to do the day hike.

If you repeatedly enter the daily lottery, you will eventually be successful, but if they charge the $10 to enter each day, that can cost $$$.

You can read up on the daily lottery here. That web page has links to the best success rates for the daily lottery last year. Mid-week days show the best success rates.

And then there is always the no-permit-required period, from about mid-October to mid-May, when the cables are "down". No permits required at all. But if you are a bit intimidated by heights and such, that would not be a good idea. If you talk to park personnel, they always try to talk people out of doing the cables-down hike, but you will find a dozen people practically any day doing it when weather is good. Here's a link:  Half Dome with Cables Down

I was successful. Don't remember my first choice but I got Monday 9/3, which actually is perfect since I'm doing Whitney on 9/10. I usually do the cable every other year but I thought what the heck it's more fun than doing Clouds Rest or Granite/Kennedy in Kings Canyon as a practice hike.

When I wanted to hike it a few years ago, I was also unsuccessful in the "day before" lottery. From what I'd read, there was a pretty good chance of hiking up to the ranger checkpoint at the base of Half Dome and asking parties if there were any unused spots on their permits due to late cancellations or no shows. I let the ranger know what I was doing and sat down near by. I think I waited maybe 10 minutes before I got lucky when a small group of guys came up and said yes to my inquiry. Once the ranger had checked their permit, I asked her if I was good to go and she gave me the green light. No shows on permits happen all the time (as with walk up permits for Whitney) and I wouldn't hesitate to try the same strategy again as long as it's for just one or two people.

The daily lottery after Labor Day is a pretty good bet. I'm usually successful after one or two tries that time of year.

This is the fourth year in a row I haven't been able to get a spot in the half dome lottery. Starting to think the system is rigged.

What range of dates were you requesting? The odds of getting a September date is over twice as much as it is earlier in the year. June is the hardest month and of course Saturday is by far the most sought after day so I never even bother to ask for that day.

https://www.nps.gov/yose/planyourvisit/hdpermitsapps.htm

Requested all Fridays and Saturdays in June

My boyfriend and I plan to summit Whitney on 9/10 also! We will be heading to Yosemite after and I am hoping to get half dome permits via the daily lottery.

I did get a wilderness permit with the cables add on to camp overnight at Little Yosemite Valley on October 1. Will go up the cables the morning of October 2.