Originally Posted by
californiadreamin'
Baggage will have to be claimed at YUL; there is no checked baggage overnight storage offered by an airline in North America (if at all).
A quick search on admtl.com reveals that there is a 24hr Cloakroom in the public area, outside Arrivals: (514) 633-2076. Perhaps they provide such a service or can refer you to a vendor that does.
http://www.admtl.com/Passengers/Aero.../Services.aspx
Cool. They do provide such a service. There is a PDF link from the site you provided with a schedule of rates, which includes the rates for storing a suitcase ($5.00 to $8.50, depending on size). Good deal. Thanks.