The effects of gas extraction operations on livelihood activities among communities remained unknown albeit the extractions pursued in Mtwara District of Tanzania. This paper analyses the changes in local livelihood activities due to gas extraction operations in the district. The paper uses the Sustainable Livelihood Framework (SLF). Data were collected through a household survey (n=260,) focus group discussions (n=8) and key informant interviews (n=15). Quantitative data were analysed using IBM SPSS Statistics whereby descriptive and multiple response analyses were performed. Qualitative data were analysed using content analysis method to supplement the quantitative information. Results show a decline in; fishing activities from 58.5% to 17.65%; decline in crop business from 36.9% to 8.92%; decline in petty business from 12.3% to 9.2%; boat driving and repair 10.0% to 3.05% during gas extraction respectively. Also, the paper reveals an increase in; sea-shells collection from 1.75% to 39.2%; farm labour in neighbouring villages from 1.65% to 5.4% and an increase in other non-farm activities like carpentry, brick making and motor circle and bicycle repair to closer villages. The study concludes that after introduction of gas extraction operations local community’s livelihood activities have changed. We recommend more investment in education and vocational training to equip local communities with skills to engage in gas extraction industries and diversified income activities. Building rural infrastructure will improve transportability and will create job opportunities for poor households.