For coverage to begin January 1, you need to act soon. By Kimberly Lankford, Contributing Editor December 20, 2013 When do I need to sign up for health insurance on the marketplace for coverage to begin on January 1? What happens if I don’t make the deadline?SEE ALSO: President Obama Allows Insurers to Extend Canceled Health Insurance Policies You must enroll by December 23 for coverage to begin on January 1. The original deadline of December 15 was extended by a week because of the problems with HealthCare.gov during the beginning of open-enrollment season. But your coverage won’t be effective until you pay your first premium, so get ready to pay that bill as soon as it arrives. Many insurers have agreed to provide coverage retroactively to January 1 as long as you pay your first premium by January 10, but some require you to pay the premiums by December 31. These rules can vary by state -- for example, if you buy insurance through Covered California (the health insurance marketplace in California), you need to pay the bill by January 6 for the coverage to take effect retroactively to January 1. Sponsored Content You can still get coverage if you don’t meet that deadline, but it won’t take effect right away. Starting in January, if you sign up by the 15th of the month, coverage will begin by the 1st of the following month, until open enrollment ends on March 31. Advertisement You won’t have to pay a penalty for not having insurance as long as you get coverage by March 31 (see The Lowdown on the Health Insurance Penalty), but you could end up going a few weeks without coverage if you wait beyond December 23 to buy a policy. And if you don’t sign up for a policy by March 31, you may need to wait until open enrollment begins again next fall to buy a policy. There are a few exceptions to the rules. A life event, such as getting married, having a child or moving to a new area, can qualify you for a special enrollment period (see How can I get coverage outside of open enrollment? for details). Also, the Department of Health and Human Services announced on December 19 that people whose policies were canceled will be eligible for a hardship exemption from the penalty for not having coverage in 2014 if they believe the policies on the exchanges are unaffordable. They can also qualify to buy a high-deductible catastrophic policy, which had been available primarily to people under age 30. See the information for people with canceled plans for more information about your options and special resources. If you want coverage to start on January 1, enroll as soon as possible. At HealthCare.gov, the federally run exchange where residents of 36 states can buy coverage, you can see plans and prices and estimate your subsidy before you buy -- features not available when the site was first launched. Many state exchange Web sites are doing much better now, too, but they are all reporting heavy volume at their call centers as people ask questions before the December 23 deadline. See How do I apply for Marketplace coverage? for several ways you can enroll in a plan and get help. Also see Tips to help you enroll in Marketplace coverage for information that can help your enrollment go as smoothly as possible. States that run their own exchanges also have sign-up advice and links to local sources of help on their Web sites; you’ll find links to the state exchanges at HealthCare.gov. Got a question? Ask Kim at email@example.com.