The K-3 nonimmigrant visa is for the foreign-citizen spouse of a U.S. citizen. This visa category is intended to shorten the physical separation between the foreign-citizen and U.S. citizen spouse by having the option to obtain a nonimmigrant K-3 visa overseas and enter the U.S. to await approval of the immigrant visa petition. K-3 visa recipients subsequently apply to adjust status to a permanent resident. A K-3 applicant must meet requirements of an immigrant visa as the applicant who applies for the visa must have a immigrant visa petition filed on his/her behalf by his/her U.S.citizen spouse. It is also important to note that a foreign citizen who marries a U.S. citizen outside the U.S. must apply for the K-3 visa in the country where the marriage took place.
K-3 visa is for a person who is validly married to a U.S. citizen. Applicant must have filed an I-130 petition, and the beneficiary seeks to stay in the U.S. during the time he/she awaits for approval. If the I-130 petition was denied, K-3 status is terminated 30 days after the denial.
A spouse is a legally wedded husband or whife which also include the the marriage where same-sex partners are involved. Merely living together does not constitute to be a qualified marriage, and in case of polygamy, only the first spouse may qualify for K-3 visa.
An unmarried children of K-3 need to prove that he/she is the child of a K-3 to receive a K-4 visa. Children who received K-4 doesn't need to travel with K-3 as long as the validity of K-4 status is valid.