We examined the prevalence of price promotions (i.e., proportion of products on price promotion) and the magnitude of price promotions (i.e., size of the price discount compared to the regular price) among online alcohol retailers. In August 2023, we web-scraped product information for all alcoholic beverages available for sale in the online stores of two leading alcohol retailers in Sydney, Australia. Products were classified into five primary alcohol categories: wine, spirits, beer, cider and premix drinks. We considered three types of price promotion: temporary price discounts (e.g., 'was $5 now $4'), multi-buy discounts (e.g., buy one get one free) and 'any six' discounts (e.g., 5% off when purchased in a bundle of any six similar products). The prevalence and mean magnitude of price promotions were estimated overall and by product category and price promotion type. In total, data for 11,184 products were collected. Of these, 62% were the subject of at least one of the assessed forms of price promotion. The most frequently price-promoted category was wine (91% of products), followed by spirits (35%), premix drinks (30%), cider (28%) and beer (21%). Of all price promotions, 61% were 'any six' discounts, 31% were temporary price discounts, and 7% were multi-buy discounts. Across all price promotions, the mean magnitude of price discount relative to the regular price was 11% and ranged from less than 1% to 71%. Policymakers should consider restricting price promotions as part of a suite of strategies to reduce alcohol-related harms.