Yes. Land or property acquired with a settled intention to resell at a profit is ʿurūḍ al-tijārah (trade goods), so at the end of each zakat year you value it at its current market price and pay 2.5% of that value, even if it has not sold yet — this is the position of the four schools, based on Allah's command to spend from the good things you have earned and on the practice of the Companions such as ʿUmar, who instructed a man dealing in leather goods to pay zakat on their value. If you bought it to live in, to hold with no trade intention, or you later decided to keep it, no zakat is due on the land itself; you only pay on any rental income or sale proceeds once they sit with your other zakatable wealth for a year. If you eventually sell it, the price received becomes cash subject to the normal rules.
Q&A · Zakat
Is zakat due on land or property I bought as an investment to resell later?
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.