Send Later 是一隻 Thunderbird 的擴充套件，他的功能是可以讓使用者安排時間寄出新撰寫的郵件。
安裝完 Send Later 之後，只要在撰寫的新郵件按「檔案 -> 稍後再寄」便會跳出如上圖所示的對話框，選擇欲寄出的日期、時間再按下 Passthrough to Send Later 就行了。
目前的 Send Later 版本是 1.1.5，支援 Thunderbird 2.0。
直接安裝 Send Later (將網址拖到 Thunderbird 附加元件視窗裡)：請按我
造訪 Send Later 網頁：請按我
Hi, I was wondering if you would like to help me localize the extension in your language. I am the author of the Send Later Extension, please contact me if you can help.
Regards
Karthik
It is a very useful tool.
But I have a question.
If I use your send later extension in my thunderbitd and I would like to send one mail two days later.
Do I need to keep my thunderbird alive in my computer throught the coming two days?
Paul 你好！
當郵件排程在兩天後發送，那麼這兩天之內 Thunderbird 是不需要一直開著的。
但到了發送時間到的時候 Thunderbird 是要開著的，不然沒辦法發送郵件。