This only covers the Venice locations of the film. The rest was filmed in Essaouira, Safi and El Jadida in Morocco, and in Viterbo, Italy.
Many thanks to Lois for taking some of these pictures for me.
Desdemona’s (Suzanne Cloutier) house – Palazzo Contarini Fasan, San Marco, Venice, Italy. It’s located on the Grand Canal just across the Santa Maria della Salute church.
The back of Desdemona’s house with the external spiral staircase – Palazzo Contarini del Bovolo, San Marco, Venice, Italy.
Othello (Orson Welles) and Desdemona’s secret wedding – Santa Maria dei Miracoli, Cannaregio, Venice, Italy
Othello’s house – Ca' d’Oro, Grand Canal, Cannaregio, Venice, Italy
"There came messengers in haste to the senate" – Palazzo Ducale (Doge's Palace) courtyard, San Marco, Venice, Italy
Officers searching the town for Othello – Ponte della Paglia, Riva degli Sciavoni near the Palazzo Ducale, Venice, Italy
The senate’s staircase – Scala dei Giganti, Palazzo Ducale, San Marco, Venice, Italy
Brabantio (Hilton Edwards) tells Othello that Desdemona has deceived her father and may deceive him too – south side of Saint Mark's Basilica, Piazza San Marco, Venice, Italy
Othello asking Iago (Micheal MacLiammoir) to take care of Desdemona and to bring her to Cyprus – Piazzetta San Marco by the Palazzo Ducale, Venice, Italy
The Third Man