Quitting a job in the US on a work visa, going to Canada and re-entering on a tourist visa (ESTA waiver)

This possibly belongs on expats.SE, but given you're technically asking about the period after your work finishes we might as well do it here...

As was pointed out in the comments, new regulations were passed in 2016 that change the rules around staying in the US before/after many visas, including E3.

The first change was the formalization of the 10 day period you're referring to, which before these new regulations were passed was never actually in the laws for E-3 visas, although it was still generally accepted as being valid.

The second is a 60 day period after you cease employment where you can stay in the country, as long as your status (I-94) is still valid.

(For the exact details of these, go here and then scroll to the very bottom - section (l)(1) and (l)(2).)

If this isn't and option for you then you basically have two options :

• Leave the US, and return under VWP. If you are entering by air this will require an ESTA. As with all entries to the US there is always a risk of being rejected, but the odds of this will be very low.

• Petition USCIS for a change of status, from E-3 to B-2 (tourist). This will almost certainly be approved - but that fact is almost irrelevant. Such requests are currently very badly backlogged, so it will likely take (at least!) several months for your request for a change of status to be approved. During that time, you may legally stay within the US given that you are pending the change of status being approved/rejected. By the time they come to process your change of status, odds are that you'll have already left the country, so it will be ignored.