The Netherlands has announced that this decision will be effective from midnight 00:01, 29th December,2020.

All International passengers travelling to the Netherlands must provide a negative COVID-19 test result taken no more than 72 hours prior to departure from 00:01 29th December,2020. This rule is applicable to Dutch Nationals, Permanent Residents and those who are transiting through the country.
The rule requiring a negative COVID-19 test result is already in effect for non-EU nationals since 15th December,2020. Then, the Dutch government decided on Wednesday to apply the rule to all international passengers from 29th December,2020. The rule will apply to all international travellers, irrespective of whether or not the Netherlands is their final destination. Children under 13 years of age and travellers from Iceland are exempted.
The government also instructed the airlines to deny boarding to anyone if they fail to present a negative COVID-19 test result.
Note: This new rule will apply to all those travelling by train, coach or boat, with the exception of regional cross-border bus transport. However, it is not a substitute for the self-quarantine period of 14 days, the Dutch government stressed in a statement.
Delta and KLM have been operating quarantine -free flights between Atlanta and Amsterdam since 15th December,2020. Passengers have to present a COVID-19 test result taken no more than 5 days before departure and then a rapid test at the airport. It is unclear what effect the new 72-hour rule that is imposed by the Netherlands government for the PCR tests will have on the program.
Recently, United States also announced that it would require negative COVID-19 test results from all passengers arriving from the United Kingdom from 28th December,2020.