Niamh began her senior career at Peamount United and made her debut for the Peas against Castlebar Celtic in September of 2015. In five years at Greenogue, Niamh won two League titles including a league and cup double in 2020.

In December 2020 she left the WNL to join Scottish side Glasgow City where she played for one and a half seasons, leaving in the summer of 2022 to join Italian side Parma.

Niamh spent one season in Italy, returning to the UK in August 2023 to sign for London City Lionesses, where she spent one season. In August 2024, Niamh came back to Ireland and rejoined her former club Peamount United.

She made her first appearance back at Peamount in a 3-2 defeat to DLR Waves on 10 August and quickly took up a defensive midfield role for the team. She played in all of the Peas' remaining 10 fixtures and scored once in a 4-2 win over Bohemians at Greenogue.

In January 2025, Niamh left Peamount to join Phil Trill's squad at Galway United, becoming an immediate fixture in midfield, scoring twice that season in 22 league and cup games.

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