Investment in seaweed (Eucheuma) culture by small farmers in Indonesian coastal areas is now considerable, but there appears to be no estimates of the economic returns from this activity. After providing background information on seaweed farms, cost of establishing a seaweed farm and farm revenue from seaweed farming, we estimate the economic returns from seaweed farming using data obtained from Bali. It is estimated that the economic rate of returns in investment in seaweed farming in Bali is very high and the pay-back period for this activity on most farm surveyed was less than a year. Currently small farmers can depend on this culture as their main source of household income in areas ecologically suitable for this culture provided market-access is not too difficult. This culture would also seem to be environmentally less damaging than many existing mariculture activities, e.g. shrimp farming. In addition, it is relatively labour-intensive and does not require significant quantities of processed or imported inputs such as fertilisers, chemicals, fuel and food. Indications are that seaweed farming is likely to be economically more attractive than giant clam mariculture in Bali.