0618 GMT January 18, 2020
Planes carrying 35 prisoners from each side landed simultaneously in Moscow and Kiev, where the passengers emerged under sunny skies, AFP reported.
"We have taken the first step," Zelensky said on the tarmac after greeting and hugging former prisoners. "We have to take all the steps to finish this horrible war."
In emotional scenes at Kiev's Boryspil airport, family members embraced and handed flowers to the former prisoners, many weeping with joy.
Among those swapped were 24 Ukrainian sailors, Ukrainian filmmaker Oleg Sentsov and Russian-Ukrainian journalist Kyrylo Vyshynsky.
"I am overflowing with happiness," Natalya Mokryak, the mother of one of the sailors, told AFP at the airport. "I have finally seen this come true."
Russian state television showed the Russian prisoners emerging from the plane at Moscow's Vnukovo-2 airport used for government flights.
Anticipation had been building for days for the exchange, which involved weeks of behind-the-scenes negotiations.
Relations between Kiev and Moscow nosedived in 2014 when people in Crimea voted to rejoin to Russia and Moscow’s support for pro-Russia forces in the eastern industrial regions of Donetsk and Lugansk. Fighting there has claimed more than 13,000 lives over the past five years.
Zelensky's election in April has raised hopes that a stalled peace process could be revived.
The comedian-turned-politician vowed during his campaign to have Ukrainian prisoners in Russia returned and has said ending the conflict with Russia is his top priority.
Russian President Vladimir Putin said this week that the exchange would be "a huge step toward normalizing relations" with Kiev.
Saturday's exchange was "a very important step", Russian Foreign Ministry spokeswoman Maria Zakharova said.
"It's necessary to maintain this drive to solve problems as much as possible," she said on Twitter.
German Chancellor Angela Merkel called the swap a "sign of hope" and called for the implementation of a 2015 cease-fire deal that Paris and Berlin helped broker.
The release of Sentsov will be seen as a major victory for Kiev. The 43-year-old was Ukraine's most famous political prisoner and the subject of a star-studded international campaign calling for his release.
He was arrested in 2014 and had been serving a 20-year sentence in an Arctic penal colony for planning "terrorist attacks" in Crimea.
"I thank all the people who have fought for us," Sentsov said at the airport in Kiev, where he was greeted by his teenage daughter who wept and smiled.
The sailors, including two members of Ukraine's SBU security services, were detained last year when Russia seized three Ukrainian vessels off Crimea.
Moscow had wanted to put them on trial for violating Russia's maritime borders.
Efforts have intensified to resolve the conflict since Zelensky's election, with French President Emmanuel Macron calling for a summit of the leaders of Ukraine, Russia, France and Germany this month.