The short answer is yes. And although most visits to Tanzania are a trouble-free, violent and armed crime is increasing.
Take particular care in places frequented by tourists and expatriate residents. In Dar es Salaam, tourists and residents have been targeted in the city center, at Ubungo bus station, the Masaki/Oysterbay peninsula area, particularly at Coco Beach and along Toure Drive. In Zanzibar, incidents have taken place in Stone Town and at hotels and on popular tourist beaches.