The World Federation One Stop Fiqh

Ruling 2410

If a man gives his wife a revocable divorce (al‑ṭalāq al‑rijʿī) in the manner that will be explained in the laws pertaining to divorce, he cannot marry her sister during the prescribed waiting period (ʿiddah). However, he can marry her sister if she is observing ʿiddah of an irrevocable divorce (al‑ṭalāq al‑bāʾin). And the obligatory precaution is that a man must not marry a woman who is observing ʿiddah of a temporary marriage.