The owners of the Staffordshire bull terriers alerted Chiswick RNLI to the incident after their pets had entered the water and were rapidly drifting down the river when they got caught in the tide, at around 10.40am on Monday (July 6).
A quick-thinking crew member saw one of the terrified canines floating past the lifeboat station and pulled the dog out of the water.
A lifeboat was then launched to rescue the second pet, which was struggling to stay afloat in the middle of the fast-flowing river.
Mark Turrell, helmsman at the charity’s Chiswick RNLI lifeboat station, said: "The dog, called Ollie, was very frightened and kept swimming away from the boat.
"He was extremely tired and had ingested a large amount of water therefore we had to grab him quickly.
"There was absolutely no energy left in him and once we got him onto the deck of the lifeboat, he rolled onto his side in exhaustion.
"We let the dog rest before reuniting him with his much relieved owners and advised they take him to see a vet as soon as possible."
The rescue came just two days after the Chiswick RNLI crew launched the E class lifeboat Dougie and Donna B, to help another distressed dog, Nelson, who was cut off by the tide on the sandy foreshore near Duke’s Meadow.
He was taken aboard the lifeboat and later reunited with his owner.
Mr Turrell added: "When there is a dog in trouble, there is always a risk that the owner will go in after it and end up putting their own life in danger.
"If your pet enters the water, never attempt to follow it.
"Instead, find a safe place on the river bank and call your dog towards you.
"Dogs should always be kept on a lead if they’re close to fast-flowing rivers."
Last month, kind-hearted canoeists rescued a drowning dog from the river after spotting him while paddling downstream.
If your pet is in danger, call 999 and ask for the Coastguard.