Protesters demanded an end to colonialism as the Earl and Countess of Wessex entered the second leg of their Caribbean tour.
Edward and Sophie were greeted with about 15 people holding banners saying "reparation now", "compensation now", "down with neo colonialism" and "Britain your debt is outstanding" as they arrived at Government House in St Vincent and the Grenadines.
A visit to Grenada was called off shortly before the tour began, while the Royal Family have been warned to avoid "phony sanctimony" over slavery.
In an open letter, the Antigua and Barbuda Reparations Support Commission said it had become "common for members of the Royal Family and representatives of the government of Britain to come to this region and lament that slavery was an 'appalling atrocity', that it was 'abhorrent', that 'it should not have happened'".
The letter added: "We hear the phony sanctimony of those who came before you that these crimes are a 'stain on your history'."
It follows the Duke and Duchess of Cambridge's recent tour of the region. He and Kate were accused of benefitting from the "blood, tears and sweat" of slaves and met by a protest calling for reparations from the British monarchy.
Before the protest, Edward and Sophie were given their second red carpet and guard of honour of the tour after landing in St Vincent and the Grenadines.
Scouts, girl guides and cadets waved the national flag while Bob Marley's One Love was played on steel drums.
Sophie visited a community college while Edward went to the island's national stadium where he met athletes training for the Birmingham Commonwealth Games, beginning in late July.
The couple were also due to plant a tree marking the Queen's 70 years as monarch at the botanical gardens.