In most cases, the effective date follows the same rules that it does during regular open enrollment. So for states using HealthCare.gov and most of the state-run exchanges, that means that applications completed by the 15th of the month will be given a first-of-the-following-month effective date.
There are three states with enrollment deadlines later than the 15th of the month: Massachusetts, Rhode Island, and Washington are all the 23rd.
Applications received between the 16th (or the 24th if you’re in MA, RI, or WA) and the end of the month will have an effective date of the first of the second following month. (Marriage, loss of other coverage, and birth/adoption have special effective date rules.)
A permanent move to an area where different qualified health plans (QHPs) are available. A permanent move to a new state will always trigger a special open enrollment period, because each state has its own health plans. But even a move within a state can be a qualifying event, as some states have QHPs that are only offered in certain regions of the state. However, as of July 11, 2016, this special enrollment period will only be available to applicants who already had minimum essential coverage in force for at least one of the 60 days prior to the move (with exceptions for people moving back to the US from abroad, newly released from incarceration, or previously in the coverage gap in a state that did not expand Medicaid).
So if you move to a part of the state that has plans that were not available in your old area, or if the plan you had before is not available in your new area, you’ll qualify for a special open enrollment period, assuming you had coverage prior to your move.
HHS finalized a provision in February 2015 that will allow people advance access to a special enrollment period starting 60 days prior to a move, but this is optional for the exchanges. It was originally scheduled to be mandatory starting in January 2017 (ie, that exchanges would have to offer a special enrollment period in advance of a move), but HHS removed that deadline in May 2016, making it permanently optional for exchanges to allow people to report an impending move and enroll in a new health plan. If the exchange in your state offers that option, you can enroll in a new health plan on or before the date of your move and the new plan will be effective the first of the following month. If you enroll during the 60 days following the move, the effective date will follow the normal rules outlined above (ie, in most states, enrollments submitted by the 15th of the month will have first of the following month effective dates).
In early 2016, HHS clarified that moving to a hospital in another area for medical treatment does not constitute a permanent move, and would not make a person eligible for a special enrollment period. And a temporary move to a new location also does not trigger a special enrollment period. However, a person who has homes in more than one state (for example, a “snow bird” early retiree) can establish residency in both states, and can switch policies to coincide with a move between homes (HHS has noted that this person might be better served by a plan with a nationwide network; but those are not available in all areas).