The midfielder, who played mostly as a right-back for Ajax last season, put pen to paper on Thursday.
Isaacs initially joined the club on a loan deal from Bidvest Wits before making his move back to the Mother City permanent in September 2015.
The 30-year-old made 30 appearances in all competitions for the Urban Warriors last season.
— Ajax Cape Town (@ajaxcapetown) 15 June 2017
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