Mercer Island Park & Ride

Parking here is horrible because on weekdays, the lot is completely filled by 8:10 AM. After doing some research, it appears that the large majority of people who park here aren’t even from the island. As a resident, I hate how there is barely any parking left by 8 AM. And all the areas of commercial parking near the park and ride have began putting up signs for towing. There’s literally nowhere to park. I feel like there should be some of preference shown for island residents or more stories built for parking. It especially sucks since I sometimes have to drive to Bellevue for the park and ride when I live on this island.

light bright and safe

Agree with Jon. It’s not a large park & ride. One time when I had friends visiting during the week, I drove over to Mercer Island to park and bus into Seattle. No spaces. So I drove to Seattle and parked for free in SODO.
However, I use this place a lot during weekends, even though I live in Kirkland. Traffic usually isn’t too bad getting over to Mercer Island, and the bus options to Seattle are better.
Here’s a summary of your major central Eastside park & rides:
Overlake only gets you the 545.
S Bellevue only gets you the 550.
Issaquah and Eastgate only get you the 554.
Yarrow Point (not a P&R, but hey…) gets the 255 and 545, but with all the SR 520 construction, it’s a mess and probably not even open.
Mercer Island gets you the 550 and 554. It used to be even more awesome before the bus tunnel was open on weekends because you could stand at the same stop in Seattle to catch the 550 and 554, but now you have to make a decision beforehand. Still, this is the best place to park to take the bus downtown on the weekends.

Yes, it is difficult to find parking here during weekday work hours. I have tried this a couple times and it was jampacked and full. Same issue you will encounter at the South Bellevue Park and Ride a few miles away.
That being said, outside of work hours this is actually a really good place to park and venture into downtown Seattle from. The 550 and 554 both stop here, so the wait is not too long for a bus downtown. This is a good place to park for sporting events on the weekend or a Mariners game in the evening on weekdays. Or if you are simply doing shopping or running an errand in town on the weekend or after work.
As long as you are not trying to park here during weekday work hours, you won’t have too much of an issue here with crowding.

This Park & Ride gets filled up fast, usually by 8am. They expanded it a few years ago, but they should have added a couple more levels. Watch out for the soccer Moms and Dads who drop off their kids to catch the bus in the morning. Most will circle the park & ride, and then wait in the middle of the lane to pick-​up their kids in the afternoon, basically causing a huge cluster jam of cars.