TLDR : Answer Summary
To extend your 60-day visa exemption in Krabi, you can apply up to 30 days before your visa expires, but it's recommended to do so within the last 14 days. You will need to visit a local immigration office and bring several documents: your passport (valid for at least 6 months), a completed TM.7 extension form, passport photos (4×6 cm), photocopies of your passport's bio page and current visa stamp, TM.6 arrival card, and proof of residence (such as a hotel booking or rental contract). The extension fee is 1,900 THB, and check if your immigration office requires a TM.30 form. For convenience, getting a hard copy of documents is advisable, and some places may assist with photocopying for a small fee.