The 18-year-old reality star and 26-year-old rapper celebrated the holiday by taking a helicopter tour of New York and later shared photos from the trip on social media.
Jenner sported a pastel pink wig for the "perfect day," and wore a long, gold coat with matching pants. She and Tyga were spotted at dinner before returning to their hotel during their romantic night in the city.
Jenner and Tyga were first linked in fall 2014 and went public with their relationship at the reality star's 18th birthday party in August. The rapper told Real 92.3 he loves Jenner last week, but said he's not in a rush to marry.
"Nah, no time soon," he said of marriage. "I mean, we all gotta walk the aisle one day. I think, whatever makes you happy in life, you gotta do it. You can't plan in life too much."
Jenner denied engagement rumors in December after showing off the enormous diamond ring Tyga got her for Christmas. She previously told Ellen DeGeneres she and the rapper were "best friends" before they started dating.
Jenner's half-brother, Rob Kardashian, spent Valentine's Day with his girlfriend, Blac Chyna, who is Tyga's ex-fiancée. The 27-year-old model shares a 3-year-old son with Tyga and posted a kiss photo with Kardashian on Instagram.