During the COVID-19 pandemic, Ireland implemented a series of stringent public health measures, including lockdowns and suspension of non-urgent clinical services. To investigate the impact of the COVID-19 pandemic on the demand for and delivery of speech and language therapy (SLT) services in Ireland in 2020. Two iterations of a cross-sectional, mixed-methods online survey were distributed to speech and language therapists (SLTs) and SLT students in Ireland in the spring and autumn of 2020 using a combination of purposive and snowball sampling. The spring survey yielded 407 responses (including 14 from SLT students), while 197 respondents took part in the autumn (13 students). Survey analysis focused on questions related to the impact of the COVID-19 pandemic on delivery and demand for SLT services (student responses were excluded from analysis owing to low response rate). The largest group in respect of experience were senior SLTs (58% in both surveys). The work settings most strongly represented were HSE primary care (34.4%) and disability services (26.5%) in the spring, and HSE primary care (39.1%), acute hospitals (22.8%) and disability services (20.8%) in the autumn. We used descriptive statistics, including distribution analysis, to analyse the quantitative data. Free text data were interrogated through a variant of a conventional qualitative content analysis. In the spring, cessation of face-to-face services featured prominently (reported by 65.6% versus 14.2% in the autumn), across SLTs' work settings, except acute hospitals. Lower demand was reported by 42.5% in the spring, while in the autumn, 48.7% indicated that demand was higher. SLTs experienced large-scale redeployment (spring: 45.9%, autumn: 38.4%), with HSE primary care SLTs redeployed most (spring: 71.7%; autumn: 62.3%). The need to suddenly pivot to telehealth was a significant challenge in terms of training, technology and logistics. New ways of working emerged and gradually, telehealth became more embedded. SLTs also had to adapt to working with evolving public health measures, such as space restrictions and personal protective equipment (PPE) requirements. Across the two survey iterations, SLTs reported tensions between demands and capacity: while referrals and demand initially decreased in the spring, this led to increased backlog and longer waiting lists, ongoing and increasing pressure on clinicians and services, and negatively impacted clients and families. The COVID-19 pandemic had a significant negative impact on SLT services in Ireland. Going forward, the SLT profession and its services will require sustained support to mitigate long-term negative consequences, such as increased waiting lists. What is already known on this subject The negative impact of the COVID-19 pandemic on SLT services has been examined in several countries. Ireland imposed more stringent pandemic-management measures than many other countries, and it was therefore warranted to investigate how SLT services in the country were affected. What this study adds to the existing knowledge Face-to-face SLT services effectively ceased in most non-urgent contexts in spring 2020. This coincided with large-scale redeployment of SLTs to non-SLT contexts. By autumn 2020, demand had increased again, but not all services had recommenced, and redeployment was still a factor. Although SLTs adapted to the ongoing changes imposed by the pandemic, they voiced concern about increasing backlogs and longer waiting lists, ongoing and increasing pressure on both SLTs and services, and negative impacts on clients and families. What are the actual and clinical implications of this work? The COVID-19 pandemic had a significant negative impact on SLT services in Ireland. Going forward, the SLT profession and its services will require sustained support to mitigate long-term negative consequences, such as increased waiting lists.