The alarm was raised after the pair, reported by Milford Haven Coastguard to be men in their 50s and "very experienced", failed to return to their dive boat in the area of Strumble Head, near Fishguard.
An air and sea search was launched at about 5.30pm - but the men's location and pick-up four miles offshore, by an RAF rescue helicopter from Anglesey, was made as darkness fell.
Fortunately the divers were well equipped for such an emergency, with strobe lights, torches and flourescent elements to their clothing.
"They did all the right things and it made dusk the best time to find them," said the Coastguard. It is probable that, without the lights, the men would not have been detected.
They would have faced a night at sea before searches could have been resumed - and, at worst, been whisked away by the currents, never to be seen again.
The men, the Coastguard added, were alright except for being "very cold".
The incident came four days after another separation episode, near North Haven on Skomer Island.
A diving RIB put out a Mayday call when it broke down and was unable to continue tending its divers in the water.
Luckily the call was intercepted by another dive boat in the area, which was able to find and take aboard the stricken boat’s divers, who had managed to gain the shore and scramble on to rocks.
The rescuing dive boat towed the other over to a mooring buoy, where examination revealed a blocked fuel filter. This was cleared and both boats were able to make their way back to harbour.
The emergency services, which had remained in touch throughout proceedings, were stood down.
Related link
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