Seaweed farming has become a well developed industry in Tanzania over the last decade. It is a significant export earner as well as an income and employment generator in coastal communities where it is practiced. The Tanzanian government has called for the aggressive expansion of seaweed farming in the recently adopted national Seaweed Development Strategic Plan (SDSP 2005). It targets the expansion of the “cottonni” variety of seaweed which commands a higher farm gate price than the “spinosum” variety. However, spinosum is more widely grown within the country at present than cottonnii which faces the die-off problems, The die off cycle of the cottonnii variety typically occurs after the heavy rainy season (March to May) and most likely due to water salinity, sedimentation from run-off and/or temperature differentials during this period (Mmochi et al. 2005). In order to help promote the expansion of the seaweed sector, a better understanding of how coastal communities adapt and incorporate seaweed farming into the mix of household livelihood activities is needed along with assessments of the relative advantages and disadvantages of the two varieties of farmed seaweed. In addition, seaweed farming is often promoted as an “alternative” livelihood that can help reduce pressure on overexploited nearshore and small-scale fisheries. However, few empirical studies have been conducted to assess the degree that seaweed farming actually functions as an alternative. This paper attempts to shed light on these issues. It compares two communities, one which exclusively grows the cottonni variety of seaweed and another that grows only the spinosum variety of seaweed.