A contract worth EUR 15m was signed with the Iranian national telco this week, while another EUR 21m contract is to follow shortly, Iskratel said on Friday.
The company will provide access to broadband internet to users from seven Iranian provinces, mostly using optical technology GPON, and modernise TCI's core network.
It had won the deal together with three global companies Huawei, FiberHome and Zyxel.
"We've won both deals, because we've got good referential solutions that we've successfully implemented in several countries. Our other advantage is that we carry out the entire project ourselves.
"We're in charge of the entire development process and production and we have our own brand," Iskratel CEO Željko Puljić told the daily Finance.
Both projects are to be finalised by the end of the year.
The deal with TCI is in line with the 2015 strategy, which was recently revived and which pinpoints telecommunications, energy, transport and public security as key areas of cooperation.
Next, the company will strive to get railway projects. "We have good references in this area from Slovenia and Russia," Puljič said.
Iskratel has been focussing on the Iranian market since 2014. In early 2016, it opened offices in the country with three other Slovenian companies.
The company, employing 950 people, generated EUR 95.6m in revenue last year, an operating profit of EUR 2.1m and a net profit of EUR 7.2m. The plans for this year include higher operating as well as net profit.