I'm planning to leave the US before the 2 year mark so I can claim the UK-USA tax treaty from J1 visa postdoc appointment. However, once I end my appointment I want to spend a few week to pack up, travelling to Hawaii ect. Can I go to Canada for a few hours/a day and return to the USA on an ESTA and not cause issues with the tax treaty staying over 2 years? I know in other threads it says if you return on a different visa type you don't have to repay anything, but I know this is in relation to a new job rather than tourism.

I know there might be an issue reentering on an ESTA by border staff as they think I might be trying to overstay, but that is a separate issue than what I am concerned with here which is being considered to stay more than 2 years and therefore having to pay back all the tax money. Regarding the border staff, if I do this I will have a return ticket to Hawaii and NZ and onwards after that, and anything else necessary to prove I do not plan to overstay.

Thanks!

What follows is no advice; just merely my personal layman thoughts.

ESTA eligibility depends on both your current situation and future intentions. Both will be evaluated at the point of attempted border entry.

Will you have any ties to the US remaining once you depart? If so, it could complicate your ESTA eligibility.

What are your intentions once you enter on ESTA? If purely a leisure roundtrip trip as a tourist, then you may be ESTA eligible.

You may want to depart to an ex-North America destination (e.g. UK) in order to “reset” your non-immigrant status.

Once you determine that you are indeed ESTA eligible, you may want to apply for ESTA while you are still in the country (US) and see if it gets approved (may take 72 hours).