Background: Harm reduction services to people who use drugs (PWUD) in Russia are insufficient in terms of quantity, government endorsement, and accessibility. The situation has recently deteriorated even further because of social distancing measures of the COVID-19 pandemic. Several organizations have started to provide some harm reduction services via online platforms by web outreach. However, little is known on how online outreach services are organized and implemented. Drawing on the example of St. Petersburg-based NGO “Humanitarian Action,” we explored web outreach work in Telegram instant messenger. Methods: Our data were comprised of 4 semi-structured interviews with the NGO staff and 301 cases of web outreach work with PWUD. We used thematic analysis to study the process of web outreach, harm reduction service provision, and needs of PWUD. Results: Three stages of the process of web outreach work were identified: clients initiating communication, NGO workers addressing clients’ needs, and NGO workers receiving clients’ feedback. Communication proceeded in group chat or direct messages. Challenges in addressing clients’ needs happened when clients turned for help after hours, sent recorded voice messages, sent unclear messages, and/or were unwilling to transition to telephone communication. All web outreach workers reported receiving only positive feedback on their work. The needs of PWUD were categorized into two major themes, depending on whether they can be addressed fully or partially online. In cases of online only provision of services, web outreach workers helped PWUD treat minor injection drug use complications, obtain verified harm reduction information and receive general psychological support. In instances of partial online services provision, PWUD were assisted in getting treatment of severe injection drug use complications, overdoses, and in accessing offline medical, psychological, social, legal and harm reduction services. Conclusions: Our research demonstrated that web outreach work is a convenient tool for delivering some harm reduction services to PWUD either partially or completely online and for recruiting new clients (including hard-to-reach PWUD that avoid attending brick-and-mortar facilities). Harm reduction organizations should consider incorporating online harm reduction services into their activities. However, further research is needed to explore relative advantages and disadvantages of online harm reduction services. © 2020, The Author(s).