Yes, donating blood is halal (permissible) in Islam.
Islamic scholars generally agree that both donating and receiving blood transfusions are permissible acts. Blood is considered a renewable resource in the body, and donating it, when done safely and without causing harm to the donor, is considered an act of charity (Sadaqah) that can save lives.
Therefore, donating blood is considered a commendable and permissible act in Islam, as it aligns with the values of helping others and preserving life.