The 33-year-old centre-back has been assessing offers on his table since he left Tottenham at the end of the season when his contract expired.
He has been heavily linked with a move to Italy this summer with Roma, Napoli and Inter all interested in the experienced defender.
But Benfica seem to have won the race for his signature following talks between the club and his representatives.
Vertonghen will report for a medical today with the Portuguese champions ahead of the move.
Once the medical is done, the defender will sign a three-year contract with Benfica on Friday.
Benfica’s willingness to offer a longer contract compared to the proposals on his table from Italy played a key part in his decision-making process.
The Portuguese club also offered Vertonghen the chance to continue to play Champions League football next season.
