It comes after France banned travel to and from the UK without a "compelling" reason as concern grows in Europe over Britain's Omicron situation
People travelling from Britain to Germany will have to quarantine from midnight on Monday as the country tries to slow the spread of Omicron.
Regional health ministers urged the government on Saturday to introduce tougher rules amid surging cases of the variant in the UK.
They called for a two-week quarantine period, including for vaccinated travellers.
"The spread of Omicron in the UK is very evident... We have to prevent the spread for as long as possible and slow it down as much as possible," the ministers said in a statement.
People coming from the UK must also provide a negative coronavirus test under the new rules.
It comes after France announced a ban on travel to and from the UK unless there is a "compelling" reason - and tourism and business do not qualify.
That order is now in force.
The Netherlands is also bringing in a tough four-week lockdown on Sunday to slow Omicron, with non-essential shops, bars, restaurants, and other public places to close.
Infections in Germany rose steeply in October and November but have fallen this month, with just under 51,000 reported on Friday.
Like Britain, it is ramping up its booster vaccine programme and on Wednesday hit a new one-day high when 1.5 million jabs were administered.
The UK is currently Europe's Omicron hotspot and reported more than 10,000 new Omicron cases on Saturday - three times as many as Friday.
Total cases exceeded 90,000 for a second day running.
Senior government scientists say extra restrictions are needed to prevent the NHS from being overwhelmed by patients in the coming weeks.
Ministers are drawing up plans for a two-week "circuit breaker" after Christmas, according to the Times, which could see restrictions on indoor mixing and limit hospitality businesses to outdoor service.