December 25 - The first Christmas of the War

A series of isolated incidents take place on the Western front where unofficial truces are observed by British and German soldiers. In some areas gifts are exchanged, carols are sung, and games of football take place.

 
Following these incidents, Allied Commanders order that future participants will be shot, and these incidents were not repeated in later years.

The British launch an air raid on Cuxhaven using aircraft launched from "seaplane tenders", or early aircraft carriers. Aircraft of the  Royal Naval Air Service were used. They flew over the Cuxhaven area and dropped their bombs, causing damage to shore installations. Flight Magazine reported the raid as, "the first employment of the seaplanes of the Naval Air Service [sic] in an attack on the enemy's harbours from the sea, and, apart altogether from the results achieved, is an occasion of historical moment."

In France, the 26th Brigade RFA fires in support of infantry.