Tanzania's aviation authority announced that it will not permit any Kenya Airways flights from Nairobi to land in Dar es Salaam effective next Monday.
There are usually three scheduled services on this route every day.
The decision to prevent the flights comes in retaliation to a move by Kenya to not allow any all-cargo flights operated by Air Tanzania to land in Nairobi.
In a statement from the Tanzania Civil Aviation Authority, it added that Kenya's move went against a 2016 agreement between the two countries.
While other airlines ply this route, this tit-for-tat action could make things more expensive and disrupt the travel plans for thousands of tourists and businesspeople who have come to rely on Kenya Airways.