This geographic dataset (GDS) contains the geographic location of the active and historical tide gauge stations operated by the Hydrographic Institute, as well as the corresponding sea surface height (SSH) observations in near-real-time (NRT). SSH observations (https://vocab.nerc.ac.uk/collection/P07/current/CFSN0374/) are provided in Coordinated Universal Time (UTC, ISO 8601) and referenced to the Hydrographic Zero (ZH, EPSG:10349). Quality control (QC) codes comply with the vocabulary available at https://vocab.nerc.ac.uk/collection/L20/current/. Processing levels follow an internal convention, where L1 corresponds to data without quality control and L2 to data with automatic quality control (e.g., range checks, spike detection, and temporal consistency tests). Active tide gauge stations: tide_obs_stations_nrt Near-real-time data without quality control (L1): tide_obs_data_nrt_l1_min — NRT data without quality control (L1), 1-minute sampling frequency, 1-minute latency, and an 8-day rolling time window tide_obs_data_nrt_l1_sec — NRT data without quality control (L1), 10-second sampling frequency, 1-minute latency, and an 8-day rolling time window Near-real-time data with automatic quality control (L2): tide_obs_data_nrt_l2 — NRT data with automatic quality control (L2), 5-minute sampling frequency, 1-day latency, and a 15-day rolling time window Historical tide gauge stations: tide_obs_stations_hist To access the complete observation time series, or specific historical periods, a request should be sent to cedencia.dados@hidrografico.pt. This dataset is part of the High-Value Datasets (HVD) identified under Implementing Regulation (EU) 2023/138 of Directive (EU) 2019/1024 on open data and the reuse of public sector information. Citation: Instituto Hidrográfico (2026): Rede de estações maregráficas - Observações. https://doi.org/10.71683/107bf4e8-ca3e-4bb7-9439-b99f631eee57