Start your day at the Fort Kochi Beach, perfect to sit and relax and watch the fishing activities and ferries. Visit the Chinese Fishing Nets and later head to Mattancherry Palace to explore the history of Kochi and its rulers. A lovely walkway is the Marine Drive with its backwaters, mangrove forests, and coconut palms. In the evening, take a stroll at Jew Town to find souvenirs and trinkets.
Start early in the morning to visit the famous 14th century Beypore Beach with its traditional wooden shipbuilding and fishing boats. Later, head to the Kozhikode Beach, which has a lighthouse with a gorgeous panoramic view of the Arabian Sea. Visit the Kozhikode Planetarium and end the day trying the delicious local cuisine at Zain's Hotel.
Starting with Sree Padmanabhaswamy Temple - its architecture is worth looking at and history is interesting. After that, a visit to the nearby, Napier Museum with its rich collection of Mughal Miniatures, rare coins, and Buddhists and Hindu sculptures. Followed by a little stroll to reach at the Kuthuriayar Palace, which is now converted into a museum showcasing the traditional Kerala and Travancore arts.
If you have more time, you could also consider adding a stay at the Munnar Tea Plantations or visit backwaters in Alappuzha. For those with less time, consider excluding the Kozhikode part.