In most cases, your coverage selected during open enrollment takes effect on January 1. But in most states, enrollments completed after December 15 will have coverage effective February 1. And in states where open enrollment continues into the latter half of February, it’s possible to have coverage effective March 1.  If you are already enrolled in an individual-market plan and you pick a different plan during open enrollment (in most cases, by December 15), your current plan will end on December 31 and your new plan will take effect seamlessly on January 1 (assuming you pay all of your premiums when they’re due). If you’re currently uninsured and have to wait until January for a plan to take effect, a short-term medical plan can bridge the gap for you, as long as you’re fairly healthy. Short-term plans are available in most states, and the coverage can take effect as soon as the day after you purchase your plan. So a short-term plan can provide peace of mind just in case you end up with an unexpected emergency before your new coverage takes effect. (You can select your state on this page to see how short-term plans are regulated and which options are available to you). But note that short-term plans should not be thought of as a viable replacement for regular individual major medical coverage. If you’re relying on one temporarily, you’ll definitely want to sign up for an ACA-compliant plan during open enrollment. If you enroll during the open enrollment period but you also have a qualifying event, you may be able to get coverage before the start of 2023. For example, if you get married and apply for coverage in November, you could have a December 1 start date if you use your special enrollment period, whereas you’ll have a January 1 effective date if you just enroll under the normal open enrollment period rules. So if your special enrollment period overlaps with open enrollment, you might want to utilize your special enrollment period in order to get an earlier effective date. But keep in mind that the plan will then renew on January 1, which means you’ll have a nearly immediate rate change and potential benefits change for the new year.