Within the Netherlands you can travel freely. Are you coming from another country? Check which color code the Dutch government has given your country at netherlandsworldwide.nl
Green or yellow
Almost all countries have a green or yellow color code. If you come from a country with a green or yellow color code, you can travel freely. You do not need to show a negative test or go into (home) quarantine on arrival.
Orange
This color code is given to a country if a dangerous new variant emerges that has not yet been detected in the Netherlands.
If you are traveling to the Netherlands from a country with an orange color code, a negative PCR test or vaccination or recovery certificate is required. This applies to everyone from 12 years and older. Home quarantine is also recommended upon arrival in the Netherlands, even if you have been vaccinated, but the quarantine is not mandatory.
Check
Want to know what you have to comply with when you travel (back) to the Netherlands? Do the online check at reizentijdenscorona.rijksoverheid.nl.