The Immigration and Nationality Act requires a K-1 nonimmigrant to enter into a valid marriage with their U.S. citizen fiancé(e) within 90 days of being admitted to the United States in K-1 status. K-2 nonimmigrants are admitted as the minor children of their K-1 parents. K-1 nonimmigrant status automatically expires after 90 days and cannot be extended.

However, as noted on our Visas for Fiancé(e)s of U.S. Citizens page, if the marriage between a K-1 nonimmigrant and their U.S. citizen fiancé(e) takes place after the 90 day period, the U.S. citizen spouse may file Form I-130, Petition for Alien Relative, on behalf of the former fiancé(e), based on the marriage. The U.S. citizen spouse may also file Form I-130 for the K-2 stepchild as long as they meet the definition of stepchild under INA 101(b)(1)(B). See our Bringing Spouses to Live in the United States as Permanent Residents page for more information.

Extending the Following-To-Join Timeline for K-2 Nonimmigrants

A minor child of a K-1 nonimmigrant who wants to join their K-1 parent in the United States at a later time (called “following to join”) may be eligible for a K-2 visa for up to one year after the Department of State issues the K-1 principal’s visa. The K-2 child may follow to join even after the K-1 principal marries their U.S. citizen fiancé(e) and acquires lawful permanent resident (LPR) status.

While the COVID-19 pandemic continues to affect worldwide consular services and travel, the Department of State may extend the one-year follow to join period for an additional 180 days if the child demonstrates that the reason they did not obtain a visa within one year of the K-1 principal receiving their visa or travel to the United States on a previously issued K-2 visa was a direct result of:

• The worldwide suspension of visa services;
• COVID-19 related travel restrictions; or
• Other COVID-19 factors which were beyond their control.

This relief does not affect rules related to fees or fee collection, or other eligibility factors for K-2 status or a K-2 nonimmigrant’s eligibility to adjust status.

From https://www.uscis.gov/about-us/uscis-response-to-covid-19.