Parking is available at the Lafayette garage next to the meeting venue.
https://www.hyatt.com/en-US/hotel/massachusetts/hyatt-regency-boston/bosto/maps-parking-transportation.  It is $40 a day.

The Boston Common garage is $32/day. It’s a 0.5 mile walk to the hotel.
https://bostoncommongarage.com/index.html#pricing

The app Park Whiz shows many options near the hotel for around $20.00 but be sure to tell the app what days/times you are arriving and leaving and check to make sure overnight parking is available. All of those details affect the price.  https://www.parkwhiz.com/destination/Avenue-De-Lafayette-Boston-MA/?lat=42.352637119783964&lng=-71.05981133150482

Another option is to park at a Massachusetts Bay Transportation Authority (MBTA) garage and take a train into the city.

If approaching Boston from the WEST

Riverside MBTA
367 Grove St, Newton, MA 02466
https://www.mbta.com/stops/place-river
Overnight parking is allowed.
Mobile app: PayByPhone #4372
Daily fee: Mon-Fri: $6 | Sat-Sun: $3

To get to the meeting venue you would take the green line train to the Park St. or Downtown Crossing stop. The hotel is a 0.3 mile walk from either station.
It’s a 40 minute train ride and lovely tour of neighborhoods outside of Boston and a round trip ticket is $4.80

If approaching Boston from the NORTH

Alewife Station  (named after Alewife Brook, which does indeed support a population of Alosa pseudoharegus, it’s part of the Mystic River watershed.)
Alewife Brook Pkwy and Cambridge Park Dr, Cambridge, MA 02140
https://www.mbta.com/stops/place-alfcl
Mobile app: PayByPhone #4241
Daily fee: Mon-Fri: $9 | Sat-Sun: $3

Overnight Parking Allowed

To get to the meeting venue you would take the red line train to the Park St. or Downtown Crossing stop.
The hotel is a 0.3 mile walk from either station.  Round trip ticket is $4.80.

River Bonus! You’ll go over the Longfellow bridge over the Charles River that is part of our meeting logo! https://en.wikipedia.org/wiki/Longfellow_Bridge

If approaching Boston from the SOUTH

Quincy Adams MBTA Garage
Burgin Pkwy and Centre St, Quincy, MA 02169
https://www.mbta.com/stops/place-qamnl

Take the red line train heading to Alewife and get off at the Downtown Crossing or Park St. station. Both are a 0.3 mile walk to the hotel. It’s a 30 minute train ride to Park St and round trip is $4.80

Overnight Parking is allowed

Payment Methods: Mobile App, Invoice
Mobile app: PayByPhone #4518
Daily fee: Mon-Fri: $9 | Sat-Sun: $3

River Bonus! You’ll get a lovely view of the Neponset River

This is a list of train stations that allow overnight parking.
https://www.mbta.com/parking/overnight-parking