Does an arrest that never led to a conviction still create inadmissibility problems?

An arrest alone, with no conviction, generally does not trigger the criminality grounds of inadmissibility, since those grounds are built around convictions, or, in narrower circumstances, admissions of having committed an act that would be an offence. Simply having been arrested, charged, and later released, acquitted, or having charges withdrawn or stayed is not the same as being convicted.

That said, an arrest can still matter in practice. Officers ask about past arrests and charges on application forms, and failing to disclose one when asked — even without a conviction — can raise a misrepresentation problem that is entirely separate from, and can be more serious than, the underlying incident itself. An arrest can also prompt an officer to look more closely at the surrounding facts, particularly if the conduct alleged could point to another ground of inadmissibility, such as security or organized criminality concerns, which don't always require a conviction to be raised.

The safest approach is always full disclosure: list the arrest, explain the outcome, and provide supporting documents such as a court disposition or police records showing the matter was resolved without conviction, rather than assuming it can simply be left off because nothing came of it.