Drew and Colby Denison are married and have two children, ages 5 and 7, who lived with Colby all year. Drew, Colby and their two children are all U.S. citizens and have valid Social Security numbers. Drew deployed to Afghanistan on March 31, 2016.His last day in the combat zone was January 31, 2017. Drew's From W-2 shows: Colby's From W-2 shows $10, 200 in box 1. This was her only income. The couple did not file their 2015 tax return before Drew deployed in March 2016.It may take them a while to locate all their prior year records. Drew and Colby want to know how long they have to file their 2015 tax return. You tell them. Because Colby was in the U.S. during 2015, their 2015 return was due on April 18, 2016. They will be penalized for filing late. Their 2015 return is due on April 18, 2017 because all unfiled returns are due on the next tax filing deadline after returning from a combat zone. They have 180 days from Drew's last day in the combat zone to file their return. They have 198 days from Drew's last day in the combat zone. (180 days plus the 18 days that remained before the April 18th, 2016 deadline when Drew entered the combat zone.)