Unfortunately, this answer isn’t so simple. Technically, you can still tan with sunscreen on. How tan, however, depends on many things: How easily you tan, what level of SPF you’re wearing, what the UV index is at the time of sun exposure, etc.
“SPF refers to ‘sun protection factor’ and is a measure of the amount of solar radiation required to produce a burn on protected skin, versus the amount required to produce a burn on non-protected skin,” Marcus explained. “So, it is still possible to tan or burn with sunscreen on, but it takes a larger dose of UV radiation to do so.”
Here’s the thing: Most people are not wearing the correct amount of sunscreen, nor reapplying often enough to achieve the SPF level stated on their bottle. So yes–Some UV rays will still get through and if you tan easily, you may still get a tan even with sunscreen on.