Hi,

Are there any walkable wineries from SLO with a carry on bag? Apparently I can’t store in airport and don’t want to rent a car.

The Amtrak station will hold bags for a fee.
https://www.amtrak.com/stations/slo.html
There are several southbound Pacific Surfliner trains per day from SLO. The Goleta station is close to the Santa Barbara airport if you would want to fly there.

Downtown SLO has wine bars and a few tasting rooms. Lots of restaurants with great wine selections.

There are no walkable wineries that I know of -- tasting rooms sure. Are you actually looking for wineries/vineyards or just tasting?

Wineries near the airport, or wineries near the city center? Most of the wineries in the area are south of town, and so is the airport.

There are several wineries within 5 miles of the airport. Just go to maps.google and search wineries near the SLO airport. Lyft and Uber serve the area, and there are a few taxi companies. Depending on how much time you have and how many vineyards you want to visit, you could negotiate a price with a driver and leave your luggage in the car as you tour around.