Santiago Lucero, spokesman for Covered California, says insurers need time to review policy applications so coverage can start in the new year.
The grace period was announced Monday after it became clear that thousands of people were unable to get coverage because the website and call centers were overwhelmed.
It applies to anyone who attempted to start an application Monday, although many people were not even able to get that far.
On Tuesday, Lucero encouraged people to keep trying to reach a call center, even if they could not prove their attempts to get coverage before the deadline.
@aaparallel If you started the app by 12/23 you have until 12/27 at 8pm, but not online. You must call our Service Center or Agent.— Covered California (@CoveredCA) December 26, 2013