Off site parking at BWI
 

There seem to be several and the rate is about 3 dollars a day less than at the airport? Is one better than another as far as frequency of shuttles to the airport, etc. We will be returning after 11 pm so that is a concern. We will be gone for 2 weeks, not able to take advantage of hotel free parking due to our schedule. Thanks for your help.

I use Park'N'Go.
They operate 24/7. I have always had fine service. Their van meets us at our space and the driver loads the luggage. On the return, I never had a long wait for the van. The van takes you directly to your car. The lot is fenced and appears secure. There usually is a discount coupon on their web site.

We use Preflight, which is on the south side of the airport near the rental car facility. That's more convenient for us as we live south of BWI. As with the service described by basingstoke2, it operates 24/7, the van meets you at your car and drops you off there also. Don't know what their current rate is, but there may also be a coupon on their website. Also, there's currently a sale on parking at BWI itself through 5/16. If that's your travel dates, you might want to check the BWI website.

I've used several of them and they are just about all the same but I have been using Preflight lately. Last 2 trips, I arrived back at BWI LATE, one time around 2am. They operate shuttles 24 hrs so shouldnt be a problem there. Check out BWI website for any parking specials and coupons. Also the off site companies such as Preflight, etc. have coupons online.

Another vote for PreFlight. I flew home a couple of years ago late at night (around midnight) to 4 or 5 inches of snow, and the shuttle driver helped me clear my car.

I've used ParkNGo with great success.

I would go on the web and do a search for BWI Parking...you'll see all the possibilities and all the coupons.

Ditto Park N Go per PP. Their website has coupons and they also have a AA discount.