Day trip to Brussels and Ghent from Amsterdam?

There is fast train Thalys going directly from Amsterdam Centraal to Brussels Midi. You can consider leaving at 6:18 , arriving to Brussels at 8:08. Back 18:52 arriving to Amsterdam at 20:42. To Ghent you leave Amsterdam at 6:18 arriving to Ghent at 8:44. You will change trains in Antwerp. Back from Ghent 18:16 arriving to Amsterdam at 20:42 with change in Antwerp. You can also take Eurostar from London at 6:50 arriving to Brussels at 10:07. Train takes one hour less than it appears because of time zone change. If you want to travel in different times you can find timetable for all these trains on Deutsche Bahn website.

Neither would be an ideal daytrip from Amsterdam, but they are possible individually. Two in one day is probably a little too much. You would be short-changing yourself on both cities. As noted by the above poster, Amsterdam Centraal to Brussels is a little under two hours on the Thalys high-speed line (but of course, this does not include time to get to the station in Amsterdam), a bit less to Antwerp, where you would change trains for Gent. The same ticket will cover both the high speed premium ride on Thalys and the slower domestic train you would take to Gent.

Thanks for the info! I'll discuss this all with my travel companions...