The effective management of confined subsurface systems is often hampered by a lack hydraulic parameter data for reliable numerical modelling. The data available is often spatially and temporally sparse due to the extensive labour and set up costs required for methods such as aquifer pump tests to acquire either hydraulic conductivity and / or specific storage. This problem could be addressed by applying Tidal Subsurface Analysis (TSA) to routinely collected water level monitoring pressure data. The method utilises the naturally induced strains from globally occurring Earth and atmospheric tides on the Earth’s crust. Earth and atmospheric tides induce multiple harmonic oscillations in groundwater pressure data, which are able to be separated using signal processing techniques into the individual tidal components of various magnitudes. These components can be compared to the synthetically produced tidal or loading potentials and analysed for shifts in phase and difference in amplitude responses. These can then be used to determine storage changes and hydraulic diffusivity, thus also permeability. Here, we present principles for TSA and provide an overview of the state-of-the-art research using TSA methods for aquifer characterisation, as well as for determining confinement including a method for deriving a quantitative measure of semi-confinement.