The Russian vessels, including the aircraft carrier Admiral Kuznetsov, were being shadowed by the Navy as they sailed via the Dover Strait.
British type 45 destroyer HMS Duncan sailed from Portsmouth on Tuesday (October 18) to "man-mark" the Kuznetsov group, and Type 23 frigate HMS Richmond escorted the group from the Norwegian Sea as it steamed south.
The Norwegian military on Wednesday (October 19) released pictures taken by surveillance aircraft of the fleets sailing in international waters.
Russia's TASS state news agency said in July that the Admiral Kuznetsov would take part in a Russian operation in Syria from October to January.
The warship would carry 15 Su-33 and MIG-29K jet fighters and over 10 Ka-52K, Ka-27 and Kа-31 helicopters, it said.
The Russian deployment comes as Theresa May condemned Vladimir Putin's aggression in Syria, accusing Moscow of being behind "sickening atrocities" in support of Bashar Assad's government.