Just saw this article about a new reporting option for boaters in the Great Lakes/Buffalo district. It is an app that allows boaters to clear customs at any location. According to reports it is still in the trial stages. Here's the article from CBP.
https://www.cbp.gov/newsroom/local-media-release/new-small-boat-reporting-procedures-now-effect
The Buffalo Field Office covers Lake Ontario and the St. Lawrence Seaway.
Edit: Here's the link for the iOS app: https://itunes.apple.com/US/app/id1263234017?mt=8
https://www.cbp.gov/newsroom/local-media-release/new-small-boat-reporting-procedures-now-effect
The Buffalo Field Office covers Lake Ontario and the St. Lawrence Seaway.
Edit: Here's the link for the iOS app: https://itunes.apple.com/US/app/id1263234017?mt=8