Is there a 100% chance of getting an STD when having sexual intercourse without contraception?

not 100%…but there’s a high possibility

Nope. But I’d go get tested anyway.

Want to get information on your status for sexually transmitted diseases? See a doctor to find out your risk factors. Doctors can assess your risk factor with questions about your sexual history. This assessment will guide them towards which STDs you may be tested for. For instance, someone with a new partner or with multiple partners would most likely be tested for Chlamydia and gonorrhea.

you have a risk though not 100% it is much lesser. actually condoms (or barrier devices) are the only contraceptive device which is protective against getting stds and aids and that too if it does not get ruptured or the contents do not get spilled out during / after the act. with unprotected sex the chances of getting stds are there are many things which increase your risk of getting infected like injury to the genitals during sex, chances of getting hiv are more if person has another std, more transmission from male to female, more chances if infective particles in the blood are more/ disease is in the active phase/ recent transmission, younger age, not washing the genitals after having sex, etc. anyway if you have any doubt go to a std centre and get yourself tested for the same and for hiv immediately and then after 6 months.

nothing is 100%, but if i were you, i would get tested ASAP, and buy a box of condoms for future use.

It depends on the STD.

For example, Genital Herpes if she was in an outbreak or shedding.. highly likely, Genital warts, highly likely, HIV 1 in 2,000 chance if she has HIV.