Is it permissible to fast two consecutive days voluntarily?

Al-Wisal – which is fasting for two consecutive days or more without breaking the fast – is prohibited and considered makruh (disliked) by the majority of scholars. The Prophet, peace and blessings be upon him, used to practice wisal, but that was one of his unique characteristics. Imam An-Nawawi explicitly stated that the most correct position in the Shafi'i school is that the prohibition of wisal is a prohibition of tahrim (rendering it haram).