High-speed Ferry service is available mid-May to mid-October from Boston Harbor Cruises and Bay State Cruise Company. From Boston, the high-speed ferry to Provincetown takes about 90 minutes, which means it's possible to make the journey as a day trip, if you catch the first sailing (8:30 am for Bay State, 9 am for Boston Harbor Cruises) and return on the last one (5:30 pm for Bay State, as late as 8:30 for Boston Harbor Cruises, depending on day of the week). But this entails a somewhat long day on the boat - if you can possibly spend even just one night in Provincetown, you'll likely have a much nicer stay (and enjoy the chance for a leisurely dinner and some nightclubbing). The number of sailings per day varies a bit between the two companies - call 877-733-9425 or visit the online schedule page for Boston Harbor Cruises. For Bay State, call 877-783-3779 or visit their online schedule page. The fare is about $50 one-way, or $80 round-trip for either company.