The winger, now playing for Spartak Moscow, was not in court to hear the sentence, a spokesperson told AFP.
Previous attempts to extradite him from Moscow have failed.
Summing up in court, presiding judge M. Vaandrager said Promes was an example to many, especially young people, due to his footballing talent.
"The suspect is regularly in the news, is active on social media, and has fans worldwide," the judge said.
"This makes it even worse that he has tried to increase his wealth... by participating in major international drug trafficking.
"All things considered, the court finds a six-year prison sentence appropriate," it said in a statement.
The court said Promes had smuggled a total of 1,363 kilograms of cocaine from Brazil in 2020, through the Belgian port of Antwerp into The Netherlands with the help of an accomplice.
The ruling was based on wire-tapped conversations and encrypted messages Promes had sent under the pseudonym "Fantasma."
Prosecutors had called for a nine-year jail sentence but the court ruled they had based their request on previous cases where the punishment was too harsh.
Lawyers for Promes had entered a plea of not guilty.
In a separate case, Promes had already been sentenced to 18 months in prison and ordered to pay compensation for stabbing his cousin over a stolen necklace.
Promes won 50 caps for the Netherlands, scoring seven goals, and was part of the side that lost to the Czech Republic in the last-16 match at the Euro 2020 championships, which was played in 2021 due to Covid.
He has not worn the orange jersey since.
In 2019, Promes joined Dutch giants Ajax in Amsterdam, after a 15-million-euro transfer from Spanish La Liga outfit Sevilla.
In 2021, he left the Dutch capital for Moscow and has played for Spartak ever since, following a previous stint from 2014-2018, during which he was named Russia's footballer of the year.
