Tatiana Tsimfer, 30, and Lyubov Svirkova, 25, were shot at point blank range by an unidentified Thai man on the beach at the resort of Jomthien near Pattaya.
"The suspect was identified as Anuchit Lamlert of Kaomaikaew district in Chon Buri province. He has a previous criminal record for robbery against foreigners in Pattaya," according to The Nation's online website.
The newspaper citied police reports claiming that Anuchit had confessed to the murder but the motive remains unclear.
The bodies of the murdered tourists will be transported to Novosibirsk, a city in west Siberia, today and handed over to relatives.
Thailand's eastern seaboard resort of Jomthien, adjacent to Pattaya, is located about 110 kilometers (70 miles) southeast of Bangkok and is very popular among Russian tourists.