Answer
It is Haraam (strictly prohibited) for a boy to have a girlfriend and for a girl to have a boyfriend.
Any type of contact including dating between a Ghayr Mahram (not prohibited in marriage) male and female without a valid Shar’ee excuse falls in the category of Zina (adultery) which is a major sin and incurs the wrath and anger of Allah Ta’ala upon the individual.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai