Developed a methodology and determined tariffs for telecommunication services provided by the ‘UKRGAZTECHZVYAZOK’ branch of PJSC ‘UKRTRANSGAZ’. The project included analysis of the existing network structure, tariff policy, and cost accounting system; development of service classification and delivery models; review of ITU recommendations and national legislation; cost determination for each service; and creation of a step-by-step methodology with automation tools for tariff calculation. The results provided a transparent tariff formation system ensuring cost coverage and a justified profit margin, forming the basis for official tariff approval.