Apply via Finnish Embassy (VFS): Estonia doesn’t have an embassy in Thailand. Finland represents Estonia for visas in Bangkok vfsglobal.com. This means you will submit your application at VFS Global for Finland, but indicate your main destination is Estonia. The Finnish Embassy will process it. Be clear in your itinerary that Estonia is where you’ll spend most of your time.
Documents: Use the Finnish Schengen visa checklist but mention Estonia-specific details (like an invitation from your partner in Estonia). A personal invitation letter from your Estonian partner (in English) with their Estonian ID/passport copy and address is important. There’s no special Estonian invitation form required in Thailand’s case – the regular letter suffices.
Processing time: Allow a bit of extra time. Your file goes to the Finnish Embassy, who may coordinate with Estonia for approval. Usually it’s within 15 days, but apply early (4 weeks ahead is wise) to cover any inter-embassy communication delays.
Sponsor & ties: Provide your partner’s financial proof if they sponsor (though Finland/Estonia usually accept that easily). Still, show any Thai income or savings you have. And as always, show ties to Thailand – even if Estonia isn’t a top overstay destination, the Finnish officers will still check for job letters, etc., to ensure you’ll return.