The warship together with Merlin helicopter were on watch at the sea, when the two Russian submarines were spotted.
According to the British Navy, the Russian vessels moved underwater south along the Norwegian coast from the Arctic.
In a press statement, the RN said: “The Type-23 frigate shadowed submarines as they surfaced separately in North Sea, northwest of Bergen, Norway, on 16 and 19 July, before Nato and Baltic forces took over duties as they continued to St Petersburg for Russian Navy Day celebrations on 31 July.”
HMS Portland and Merlin were also accompanied by the Royal Air Force’s (RAF) P8 Poseidon maritime patrol aircraft to hunt and track the submarines.
Both, Type 23 frigate and Merlin are equipped with sonars, sensors and torpedoes for submarine-hunting operations.
The incident draws attention as the Russian aggression against Ukraine continues. Several nations are supporting Ukraine in its fight against the country.
As part of this, the RN’s mine hunting crews are providing comprehensive training to 80 Ukrainian sailors, as two British Sandown-class mine hunting vessels are due to be sold to Ukraine.
This training is part of the on-going UK-led military training programme to support Ukraine amid conflict with Russia.
The Sandown-class minehunters specialise in locating and neutralising mines in deep waters.
UK Armed Forces Minister James Heappey said: “The RN and British Army are working long hours and drawing on operational experience to make sure their new Ukrainian friends are sent into combat with best chance of victory.”