Lang Tengah is generally safe for solo female travelers. It's a tranquil island with fewer tourists compared to other islands in Malaysia. The locals are friendly and helpful, though like any popular tourist spot, a reasonable level of caution should be exercised. Petty crime is rare, but it's always a good idea to safeguard your belongings. At night, it's safer if you stay within well-lit, populated areas. It's also recommended to make your travel arrangements through reputable companies to avoid scams.