Cat Ba is generally safe for solo female travelers. It's a well-traveled tourist destination with a laid-back atmosphere. However, as with any travel destination, exercising common precautions such as avoiding deserted areas at night, not displaying expensive belongings and ensuring your accommodation is safe and secure is important. In case of emergency, there are basic level hospital facilities and English is widely spoken by locals. Ensure to respect local customs and dress appropriately for a more seamless visit.