A vulnerability scan runs automated tooling against your systems and reports known CVEs and common misconfigurations. It’s fast, relatively cheap, and genuinely useful as a baseline — but it can’t find business-logic flaws, chained exploits, or anything that requires understanding what your application is actually supposed to do.
A penetration test starts where a scan ends: a human tester manually explores the target, chains findings together the way an attacker would, and confirms exploitability rather than reporting theoretical risk. It costs more because it takes real time from a real person.
Most compliance frameworks that require ‘penetration testing’ explicitly do not accept a vulnerability scan as a substitute — worth checking before you scope the wrong service.