Alcohol, cannabis, cocaine, heroin and benzodiazepines account for 95% of treatment cases in Ireland. This study examines first episode treatment data from the European Treatment Demand Protocol to examine access to services based on primary problem substance. The (N = 37,550) main presenting substances were alcohol (48.2%) and cannabis (21.4%). Alcohol had the highest proportion of women seeking treatment (37.6%) while cocaine had the lowest (19.0%). Alcohol cases were the oldest (40.7 years) while cannabis cases the youngest (22.9 years). Irish Travellers had higher rates of presentation for heroin and benzodiazepines use. Alcohol had the longest duration between first use and accessing treatment (24.2 years), while cannabis had the shortest (7.9 years); these differences were statistically different compared to all other substances. Alcohol cases were more often referred by medical sources and cannabis from criminal justice and community/social services. These findings emphasise that there were considerable periods between first use and first treatment and there are different demographic presentations between different substances.