On our way to visit friends on White Head Island. You need to go to a specified customs port and tie up before you make the call. I had forgotten about pre-registering with CANPASS, guess we've been in the system for a while. As Peter says, it's a simple call to an 800 number. After giving the agent on the other end some simple information you are issued a cruising permit number that you should save somewhere. Once about 12 years ago we met a customs officer in Chester, NS. Once we told her our permit number everything was fine. Clearing back into the US is a bit more of a hassle and I'm still uncertain about how to go about it properly. If you are already in Passamaquody Bay stopping at Eastport or Lubec is no big deal. Returning was much simpler when you could check in at Cutler. We usually call ahead to the main office in Houlton. Last summer we were heading to Bar Harbor when we learned that we can also clear into Northeast Harbor, Southwest Harbor and Belfast. Jonesport is also listed as a customs port but we were pretty much told that customs officers would not appreciate being called there. We cleared into Northeast Harbor after spending the night on a mooring at Little Cranberry I. I received contradictory answers over the phone from four different officers about the legality of that move. Fortunately the pleasant young officer from the Bangor office who met us at the dock in NEH and inspected our paperwork didn't have a problem with it.