Germany, until recently heavily dependent on Russia for gas, has been seeking to diversify its energy supply since Russia invaded Ukraine in February.
The announcement came on the second day of a two-day trip to the Gulf region by Chancellor Olaf Scholz in his bid to secure alternative energy resources.
"We need to make sure that the production of LNG in the world is advanced to the point where the high demand that exists can be met without having to resort to the production capacity that exists in Russia," Scholz told journalists before the deal was announced.
The LNG delivery will be 137,000 cubic metres and the first to be supplied to a floating LNG terminal at Brunsbuettel near Hamburg, RWE said.
"This marks an important milestone in building up an LNG supply infrastructure in Germany and setting up a more diversified gas supply," RWE said in a statement.
The president of the United Arab Emirates, Sheikh Mohammed bin Zayed al-Nahyan, signed an agreement with Scholz that covers accelerating energy security and industrial growth.
ADNOC further reserved an unspecified number of LNG cargos for Germany in 2023, the state news agency (WAM) reported on Sunday.
Scholz travelled to Qatar after his meetings in Abu Dhabi. On Saturday, he held talks in Jeddah with Saudi Arabia's Crown Prince Mohammed bin Salman.
(Reporting by Andreas Rinke and Moataz Mohamed; Writing by Tom Sims; editing by David Evans and Emelia Sithole-Matarise)