Is it possible to have implantation bleeding next day after unprotected intercourse?

Yes... But if you have implantation bleeding, it is also 6-7 days after your egg was fertilized - so it wouldn't be from intercourse the day before. Most 'implantation bleeding' is not, it's usually breakthrough - implantation bleed is mainly internet gossip.

Related Questions

Does implantation bleeding start the day after unprotected intercourse?

No. Implantation bleeding occasionally occurs as the embryo attaches to the uterine lining. Implantation begins about 6 days after ovulation. Spotting a day after intercourse would not be implantation from an embryo formed on that day. Read more...