Adult Littorina littorea were collected from the intertidal zone of Helgoland (North Sea, Germany; 54°11′ N, 7°53′ E) during November 2023 and June 2024 to investigate physiological and behavioral responses to acute warming. After collection, the organisms were transported to the Alfred Wegener Institute in Bremerhaven, Germany, and acclimated for two weeks to season-specific temperatures representative of winter (10 °C) and summer (16 °C) in aquarium systems containing filtered, recirculating, and continuously aerated seawater at a salinity of 33. Animals were fed Fucus vesiculosus ad libitum throughout the acclimation period. Following acclimation, individuals were exposed to a continuous warming ramp from the respective seasonal acclimation temperature to 34 °C at a rate of 1.5 °C h⁻¹. Samples were collected at predefined temperature intervals between 10 and 34 °C for winter-acclimated animals and between 16 and 34 °C for summer-acclimated animals.The dataset contains behavioral, metabolomic, and biochemical measurements obtained from snails at the respective experimental temperatures. Behavioral observations include the time required for antenna extension and the initiation of locomotion. Metabolomic data were obtained from whole-body soft-tissue extracts using proton nuclear magnetic resonance spectroscopy using the ultra-shielded vertical 9.4 T NMR spectrometer (Advance III HD 400 WB, Bruker-BioSpin GmbH, Germany), with a 1.7 mm triple tuned 1H-13C-15N NMR probe and a Carr-Purcell-Meiboom-Gill sequence (Bruker protocol cpmgpr1d, TOPSPIN 3.5, Bruker GmbH, Germany) with water suppression. Biochemical measurements comprise heat shock protein 70 abundance and catalase activity determined from whole-body tissue homogenates. The data were collected to characterize temperature-dependent physiological and behavioral responses of L. littorea across seasons and to identify thermal thresholds during acute warming exposure.