"He arrived early on Monday morning with the aim of meeting and holding talks with Russian President Vladimir Putin," Iranian state news agency IRNA posted on Telegram.
Moscow's TASS news agency confirmed earlier that Putin plans to meet Araghchi, citing Kremlin spokesman Dmitry Peskov.
Earlier, Araghchi headed to Russia as peace efforts between Tehran and Washington hung in the balance, following a flurry of regional diplomacy and the collapse of planned talks in Pakistan.
Abbas Araghchi visited Oman between trips to Pakistani capital Islamabad and is expected to meet President Vladimir Putin on Monday, according to the Iranian ambassador.
On Saturday, US President Donald Trump scrapped a planned trip to Islamabad by his envoys Steve Witkoff and Jared Kushner.
In a sign that efforts were ongoing, the Fars news agency said Iran had sent "written messages" to the Americans via mediator Pakistan outlining red lines, including nuclear issues and the Strait of Hormuz.
Fars said the messages were not part of formal negotiations, however.
US media outlet Axios reported on Sunday that Iran had sent a new proposal to reopen the Strait of Hormuz and end the war, with nuclear negotiations postponed for a later stage, citing a US official and two other sources with knowledge of the matter.
Iranian state news agency IRNA cited the report without denying it.
A ceasefire in the US-Israeli war with Iran has so far held, but its economic shockwaves continued to reverberate globally.
Iran has sealed off the strait, cutting flows of oil, gas and fertiliser and sending prices soaring, raising fears of food insecurity in developing countries.
Hopes for a second round of talks in Pakistan had centred on a planned visit by Witkoff and Kushner, but Trump cancelled the trip, dismissing it as "sitting around talking about nothing".
On Sunday, Trump told Fox News that if Iran wanted the talks, "they can come to us, or they can call us."
Trump faces domestic pressure as fuel prices rise following Iran's closure of Hormuz, with midterm elections due in November. Polls show the war is unpopular among Americans.
Safe transit
Asked whether cancelling signalled renewed fighting, Trump said: "No, it doesn't mean that."
On Saturday, Araghchi met Pakistan's military chief Asim Munir, Prime Minister Shehbaz Sharif and Foreign Minister Ishaq Dar, before travelling to Oman and returning to Islamabad.
He later left for Russia for talks with senior officials, his ministry said.
Russian and Iranian state media confirmed Araghchi's talks with Putin, citing officials from their respective governments.
Iran's official IRNA news agency quoted Iran's envoy to Moscow, Kazem Jalali, saying they would meet in St Petersburg, Russia's second city.
Araghchi himself posted on X that the talks in Oman had focused on ensuring safe transit through Hormuz, "to benefit of all dear neighbours and the world."
"Our neighbours are our priority," he added.
Pressure to end the war has intensified as the Strait of Hormuz remains closed. Iran's Revolutionary Guards said they had no intention of lifting their blockade, which has roiled energy markets.
"Controlling the Strait of Hormuz and maintaining the shadow of its deterrent effects over America and the White House's supporters in the region is the definitive strategy of Islamic Iran," the Guards said on their official Telegram channel.
The United States has imposed a blockade of Iranian ports in retaliation.
In a statement carried by state media, Iran's military warned that continued US "blockading, banditry and piracy" would draw a response.
Israel strikes Lebanon
Israel and Hezbollah traded blame over violations of the fragile ceasefire in Lebanon, with Prime Minister Benjamin Netanyahu saying the military was "vigorously" targeting the Iran-backed militia as both sides claimed new attacks.
Hezbollah drew Lebanon into the Middle East war on March 2 by firing rockets at Israel to avenge the death of Iran's supreme leader Ali Khamenei, with Israel responding with strikes and a ground invasion.
But claims that both sides have breached a 10-day ceasefire agreed earlier this month have continued.
Netanyahu told Sunday's weekly cabinet meeting that Hezbollah's actions were "dismantling the ceasefire" while Hezbollah said it would respond to Israeli violations and its "continued occupation".
Lebanon's health ministry said Israeli strikes on the country's south on Sunday killed 14 people, including two women and two children, and wounded 37.
The state-run National News Agency reported that Israeli warplanes had struck after evacuation warnings in Kfar Tibnit.
An Israeli strike on Zawtar al-Sharqiyah, another of the flagged villages, destroyed a mosque and another religious building, the news agency said.
Israel, which reported a soldier killed in combat in south Lebanon, says it can act against "planned, imminent or ongoing attacks".
"This means freedom of action not only to respond to attacks...but also to pre-empt immediate threats and even emerging threats," Netanyahu said.