There are mosquitoes in Tanzania so travelers should be well prepared. You will need to bring repellent for mosquitoes and other insects. In coastal area and in the area around Rift valley you will encounter possibly a lot of mosquitoes. Make you take Malaria prevention before and during your travel to Tanzania. It is also recommended that you vaccinations against hepatitis A, polio and typhoid. Refer to your local health authorities to finalize your immunization recommendations and requirement