Ireland · coast guide
Understanding the coast of Ireland
This guide explains the coast of Ireland on the Atlantic; calculations, observations and product limits remain distinct.
Read a local tide
Times and heights depend on the port, datum and station timezone. Ireland’s Atlantic coast, Irish Sea and many bays should be read from a named station or model location. The Marine Institute distinguishes harmonic predictions from its regional model output, so the label matters as much as the time. A value for Galway Bay is not automatically a value for an open west-coast beach. A value from another place cannot be carried to a nearby beach. Mareloa preserves the source and timestamp of its data but does not replace the national hydrographic reference.
Tidal range and coast
Tidal range changes around headlands, in estuaries and inside bays. That variation is a local coastal effect, not a national coefficient. Start with the named prediction location, then use local charts, access information and on-site signs for the shore you are considering. Tidal range is the vertical difference between low and high water. Bays, depth and coastal shape change it, so one astronomical cycle does not create the same range everywhere. Mareloa creates no national coefficient for Ireland and infers no access from one number.
Prediction, model and observation
A harmonic prediction describes the periodic tide; a model and a station observation have different assumptions and timestamps. Wind, pressure and waves can alter conditions at the shore. Keep those products separate and do not treat a missing observation as confirmation that conditions are unchanged. An astronomical prediction calculates a periodic component. A model adds assumptions; an observation is a measurement at a station and time. Wind, pressure, waves and geography can change actual level. These categories remain separate and missing evidence never becomes reassuring.
Plan a coast visit
Bathing notices, shellfish rules, harbour restrictions and access routes are published by the relevant local authority or competent body. Check them before visiting a beach, pier or estuary. This guide helps identify sources but does not decide whether an activity is permitted or appropriate. Use this guide to understand provenance, not to decide an activity. Restrictions, health notices, access and signage are local and can change. Consult the competent authority and on-site information; Mareloa is not a navigation tool.
Reviewed source
This page cites and links to this public reference; it does not reproduce its tables.
Reviewed 2026-09-11.