The sites were blocked after an order by the country's communication commission
About 25 sites among them pornhub.com, xvideos.com and youporn.com could not be accessed on mobile phones.
Authorities instituted the ban after it was noted that porn sites were among the 100 most viewed sites in the East African nation.
UCC executive director Godfrey Mutabazi wrote to internet providers warning them against facilitating viewing of porn among Ugandans.
"Ensure that pornographic material is not uploaded or downloaded through your services," the lettters read in part.
The orders were made part of the Ugandan laws stating: "A person shall not produce, traffic in, publish, broadcast, procure, import, export, sell or abet any form of pornography and anyone who commits such is liable, on conviction, to a fine of Ush10 million or imprisonment not exceeding 10 years."
According to Pornography Control Committee chair Dr Annette Kezaabu, the numbers of porn watchers had drasticaly reduced since the ban took place.
"As I speak, we have a team that is compiling a list of other porn sites that will be blocked.
"We anticipate that some people will open up new sites but this is a continuous process," she said on Wednesday.
Porn Sites that Managed to Escape Blocking
She, however, noted that some porn sites had resulted to using proxies and had managed to slip through the sieve.
The porn control chair assured that the governmrnt would acquire new equipment to monitor any porn within Uganda's internet space.