I just arrived in Zanzibar. Entry to the country was very easy. I had to show my vaccination certificate and my online health form for Tanzania. Best is to print out both forms. You can get visa on arrival. You have to fill in 2 forms , visit 3 seperate kiosks and pay 50 Us is cash. I saw Visa card terminals but I think it is better to pay in cash. The more upfront in the airplane the quicker you are outside. For us it was 30 minutes. We had row 14 on our QR flight.