Nine people have been arrested and sentenced to one month in prison for eating in public during Ramadan, a police spokesman said.
He said the nine men had 10 days to appeal against their one-month sentences before the terms take effect.
Their sentencing, which followed complaints from other local residents, comes ahead of a call circulated on social media for a demonstration on 11th June to protect the rights of those who decline to take part in the Ramadan fast.
Although the state has the role of "guardian of religion" under the constitution, Zanzibar has no specific law banning eating in public during Ramadan.
Most restaurants and coffee shops remain shut during daylight hours over the holy month, but some establishments open behind closed curtains to prevent customers from being seen.