Information on bionomics of species composition, seasonal dynamics and insecticide susceptibility status is important to understand malaria transmission in any particular eco-epidemiological setting and for the design of effective vector control strategies. Here, adult mosquitoes were collected using CDC light traps (CDC LTs) and human landing catches (HLC) for 17 months between June 2018 and September 2020 from Lare District of Ethiopia. Larvae and pupae of anopheline mosquitoes were collected from breeding sites of Lare District and Jimma and reared to adulthood. Bioassays were conducted on non-blood-fed, 3-5-day-old emerged adult female mosquitoes using WHO insecticide-impregnated papers. spp. infection in and were identified using TaqMan qPCR. Of 11,048 mosquitoes collected, was the most common (46.20%,  = 5103), followed by (27.89%,  = 3082), () (16.04%,  = 1772) and (9.88%,  = 1091). Most of the mosquitoes (73.17%,  = 8084) were collected using CDC LTs and 26.83% ( = 2964) were captured using HLC. The mean density of , and was generally higher in June-November as compared to other months during the study period. However, the mean density of was relatively higher through November-January following the peak malaria period in Lare. , (.) and complex were susceptible to pirimiphos-methyl, propoxur and bendiocarb. However, and () were resistant to DDT, deltamethrin, permethrin and malathion, whilst members of the complex were resistant to DDT and deltamethrin. No spp. infection was detected from samples of and . There was temporal variation in mean density of mosquitoes and higher mean mosquito density was recorded during June-November (except for ). The higher outdoor mean mosquito density coupled with multiple insecticide resistance of malaria vector populations and occurrence of in the dry season call for regular monitoring and intervention considering the behavioural dynamics of species across seasons.