Within the discussion around sustainable diets, seafood consumption is still a relatively neglected field. This article discusses relevant behaviours consumers can perform to consume seafood sustainably. The predictive power of intention, descriptive social norms, trust, awareness and pro-environmental attitudes are theoretically discussed and statistically tested across two studies in regards to (a) using sustainable seafood labels, and (b) using sustainable seafood guides. Data analysis (N1 = 309, N2 = 881 Norwegian adults) shows that intentions, social norms and trust predict seafood label use across studies. The variables predicting seafood guide use are less stable which might be due to this behaviour being performed by a very small fraction of consumers only. Causal relationships have been identified in study 2 by applying cross-lagged panel analyses between intentions, trust and social norms and seafood label use. Further causal relationships were found between intentions, trust and awareness and seafood guide use. A bidirectional relationship was confirmed between descriptive social norms and seafood guide use. Potential strategies to promote seafood label- and seafood guide use, are discussed based on these results.