Should I cancel my insurance plan before I ship to BCT?

I'd wait until the morning you ship out to cancel, just in case something comes up and your ship date gets pushed out.

You should be able to call the Insurance Company and tell them what date to cancel it.
Unless you're already raised your hand and sworn the oath I would wait till afterwards.

Depends if you are AD OR Reserse/NG? If you are AD I would wait til like you 2nd week or plan ahead and let your insurance company know to automatically cancel on a certain date that way you know your insurance is in affect with the military. If you are reserve or NG I’ll keep it cause you will need it when you get back!

Are you going on AD or Res/NG?

Wait until you actually ship out. That way you are good to go.

Check with your agent, as some Insurance Policies do not insure you against accidents incurred while in the Military on a policy written prior to entering Military Service. Your policy should have some sort of reference written into it so read it and check. PS: You're in the Military the very second you raise your hand and state the oath at MEPPS.