The Syrian Orthodox Church observes six fasts:

• Fast of Nineveh: Three days commencing on the Monday of the third week prior to the Great Lent.
• The Great Lent: Forty eight days prior to Easter.
• Advent: Fifteen days commencing on the 15th of December.
• Fast of the Apostles: Three days commencing of the 26th of June.
• Fast of the Virgin Mary: Five days commencing on the 10th of August.
• Wednesday and Friday Fast: Every Wednesday and Friday around the year, except the 50 days between Easter and Pentecost and any feast of the Lord or the Virgin Mary.

Source:

Afram Barsoum (1951). Golden Key to the Divine Worship.