Two companies, Jawwal and Wataniya, started offering the services on 23 January, a report on the website Phys.org said.
Prior to that, Palestinian mobile companies had no access to the frequencies as they had been blocked by Israel.
The report pointed out that 3G services were launched in the early 2000s and 4G is common in most countries.
"We launched 3G technically and commercially about midnight on Monday (22 January), he said.
"This is a strategic step we have been waiting for for more than 10 years. We hope it has a positive effect on the national communications (infrastructure) and economy."
The service will be only be available in the West Bank for now and not in the Gaza Strip, which has been blockaded by Israel for more than a decade.
Both companies need Israeli permits to bring in the necessary equipment. Egypt has also kept its border with Gaza largely closed in recent years.