The 18-year-olds were in their final week of their three-week placement working as volunteer teachers on the East African island, when the random attack happened.
Witnesses say the girls, who are reportedly from Hampstead and Chelsea, were walking though Stone town’s narrow streets when two men on mopeds threw acid at them before speeding off.
The pair suffered burns to their faces, chests and hands and were flown to a hospital for treatment, before being discharged with minor burns.
Police, who do not know the motive behind the attack yet, released a statement confirming:
'The doctors said the injuries are relatively minor. There is discoloration but they are not expected to be scarred. It is very fortunate.'
Tanzania's minister of information, tourism, culture and sports, Said Ali Mbarouk, condemned the attack.
'It should be condemned by all citizens of Zanzibar’
‘We should co-operate with other government sectors to ensure that the perpetrators are arrested and brought to justice,’ he said.
‘And I beg our nationals, this is not something they should be doing. Tourism is the strongest pillar of our economy, so if we do such acts we are killing our economy, and our livelihoods in general.
‘So it is not an honourable thing to do, it's a bad thing and it should be condemned by all citizens of Zanzibar.’
Other recent attacks in the country include an acid attack on a Muslim cleric and the fatal shooting of a Catholic priest