Thai diplomats arrived in the Cambodian capital under military guard on Monday to restore some diplomatic ties cut after anti-Thai rioting last month.
Thailand closed its border with Cambodia and evacuated hundreds of its citizens after a mob vandalized and torched the Thai Embassy and dozens of Thai-owned businesses on January 29.
It also downgraded relations and withdrew its ambassador, Chatchawed Chartsuwan.
Charge D'Affaires Kosit Chatpaiboon, who had been airlifted out of Phnom Penh on January 30, returned on Monday along with 20 commandos and 11 embassy staff on a military flight from Bangkok.
Three Cambodian military helicopters escorted the Thai air force plane on its way to Phnom Penh International Airport.
As they stepped off the plane, Chatpaiboon and his entourage were greeted by Cambodian Foreign Affairs Ministry officials and Cambodian Prime Minister Hun Sen's personal security detail.
The return of the Thai diplomats is seen as a step toward normalizing relations between the two Southeast Asian neighbors following the riots, which were sparked by false rumors that a Thai television actress had made offensive remarks about Cambodia's famed national symbol, Angkor Wat. The actress has repeatedly denied ever making such remarks.
Cambodia has apologized and promised to compensate Thailand for the damages, estimated by Thai officials at 2 billion baht (US$46.5 million).
Following the Cambodian offer, Thailand eased some restrictions by restoring diplomatic ties to the charge d'affaires level and partially reopening border crossings for exchange of small trade.
The charge d'affaires is being housed in the former Japanese ambassador's residence, which is heavily guarded by Hun Sen's bodyguards.
Chatpaiboon said the embassy's operation will be conducted temporarily out of the former Japanese Embassy compound in the centre of the Cambodian capital.