Can you claim kids that stayed while on vacation THEN months later lived with you full time as a dependent if their parent agrees?

[Confused20]

My sisters children would come from another state for holidays and vacation to stay at my home. In mid June they came to visit and went to camp from my home. We decided they would stay for the next year. BUT I think we went back to gather their clothing from their home state. I can’t remember if it were before or after July 1st(I use this as the half way mark for the year ) . Since it wasn’t formal would the move in date be when they actually arrived and I was responsible for them (despite leaving for camp for a few days ) OR the day their mother agreed that they could live with me for the next year ? Also why IF they lived with me for 5months and 25 days but their mom forfeited her claiming them .. could I? Also IF that were the number could their previous visits in the beginning of the year count as living since they stayed in my home or NO since it was vacation ?

[DMarkM1]

 You count the nights they actually stayed with you as time with you. Also you can count the days (months) the child or dependent lived away from you towards the total time with you as long as it was for:

• Illness or other medical care
• Education (student living at school)
• Away on business
• Vacation
• Military service
• Detention in a juvenile facility

As long as the number of days with you is over 184, then in TurboTax you would select at least 7 months as time with you in the US.

[Confused20]

@DMarkM1 Thank you. May I ask one additional question ? So what IF their visit to me in June  , a relative, turned into living with me ? They came to visit me in mid June .. we returned to their home at the beginning of July for a family event ... they returned immediately back with me and never left. Would the time they went back home for the family even count as a reset date so to say or would the time they came to initially visit in June be counted ALTHOUGH they were initially considered on vacation but the vacation resulted in them moving in after the brief return in July ? 

[DMarkM1]

You are going to count all the time they were with you; the time in June and then the time once they came back from the family event.  In this case, I would say the time at the family event would not count as time with you since they didn't officially move until after the family event. 

Any time on vacation after the July return to you would be time with you as well.  

[Confused20]

Thank you @DMarkM1 ... I was afraid that because they were initially visiting in June that it would mean their mother (although she gave me permission to claim them ) would still be the only person that could claim them since I’m not their parent and the rule of “Temporary Time Away from Home

If your child was temporarily away from home, we count that as time lived with you.” being applied to my sister.