The Italian text of the Decameron is based on V. Branca's Einaudi edition (1992). Read Italian Text
The English translation of the Decameron (J. M. Rigg, 1903), while somewhat dated in its language and style, has a highly literal approach to translation which gives readers a reliable crib for exploring the original Italian text and is easily readable on its own. Read English translation
Other translations of the Decameron:
Decameron, translation sometimes attributed to John Florio, 1620.