Legislative by-elections will be held in Taipei and Nantou next year to fill the seats left by Taipei City Mayor-elect Chiang Wan-an and Nantou County Magistrate-elect Hsu Shu-hua. In Taipei, observers have picked Hsu Chiao-shin, Wang Hung-wei, Lee Guei-min, and Cheng Li-wun as possible candidates for the pan-blue camp. On the pan-green side, Ruan Jhao-syong and Enoch Wu have expressed interest in running.
A by-election for Taipei City Mayor-elect Chiang Wan-an's legislative seat will be held on Jan. 8. Candidates may register between Nov. 28 and Dec. 2. While observers say Hsu Chiao-hsin and Wang Hung-wei, both of whom were just reelected to the Taipei City Council, are the most likely candidates for the pan-blue camp, both say they are not interested in running. Former lawmaker Lo Shu-lei says she would run if recruited by the party. Other possible candidates include at-large lawmakers Lee Guei-min and Cheng Li-wun.
Wang Hung-wei, Taipei City Councilor (KMT): “The party should conduct a survey as soon as possible and then nominate the candidate that has the best chance of winning. I'm in an awkward position, as everyone knows. I was just reelected as a city councilor. My new term hasn't even started yet and I'd have to register for the election this week. Therefore, I'm not interested in running.”
Over in the pan-green camp, Taipei City Councilor Ruan Jhao-syong and Forward Alliance Chair Enoch Wu have expressed interest in running. Liang Wen-chieh, who was not reelected to the Taipei City Council, is also regarded as a possible candidate. The DPP's new acting chair will decide on a nominee.
Ruan Jhao-syong, Taipei City Councilor (DPP): “Once we have an acting party chair, he or she will make the decision. Nominees have been decided by primaries, recruitment or other methods in the past. I believe in the party's system.”
Apart from the by-election in Taipei's District 3, a by-election will be held to fill the legislative seat left vacant by Hsu Shu-hua after her sweeping victory in Nantou County. Possible candidates include KMT's Nantou County chapter head Lin Ju-bin and Nantou City Mayor Song Huai-lin for the KMT, and Jiji Township Chief Chen Ji-heng and Tseng Tsung-kai for the DPP. Tseng is the Nantou service office manager for lawmaker Huang Hsiu-fang.
九合一選舉落幕，辭去立委勝選台北市長的蔣萬安連日謝票，而他卸下的立委席次，將在明年1月8日舉行補選>中選會宣布，自11月28日到12月2日，開放有意參選者登記。目前藍營內部，才剛連任議員的徐巧芯、王鴻薇都被視為熱門人選，不過兩人都稱並沒有意願角逐，而前立委羅淑蕾大方表態，只要黨徵召將「義不容辭」，不分區立委李貴敏、鄭麗文也被點名。
國民黨台北市議員王鴻薇表示：「黨中央還是應該趕快做民調，然後去決定一個最有勝選的人，我的角色非常尷尬，大家都知道，我剛剛完成選舉，這個星期登記，我還沒有就職，所以我個人並沒有要參選的意願。」
至於民進黨部分，台北市議員阮昭雄、壯闊台灣聯盟理事長吳怡農都有意爭取，而這次選舉意外落馬的台北市議員梁文傑也被認為是潛在人選，未來將由黨中央代理黨主席徵召決定人選。
民進黨台北市議員阮昭雄說：「等到我們代理黨主席出來之後，交由主席來做裁決。過去以來我們黨部還是初選也好，徵召也好，或者是各樣方式的程序，我都相信黨的制度。」
除了北市第3選區立委將舉行補選，國民黨立委許淑華大贏南投縣長選舉，留下的立委席次也將補選，國民黨包含縣黨部主委林儒彬、南投市長宋懷琳有意參選，民進黨則是集集鎮長陳紀衡、立委黃秀芳南投服務處主任曾琮愷有意角逐。
