The geography of Kerala, which is a small strip of land between the Western Ghats to the east and the Arabian Sea to the west, not only kept the region politically and culturally separate from the rest of the world but also made it ideal for growing spices, which were in high demand in the ancient world. This led to trade with many parts of the world.
First, the first Jews are thought to have come to Kerala because of the spice trade in the area. Some people think they were traders from the kingdom of King Solomon (970–931 BC), but they don’t know when they came. Between the sixth century BC and the first century AD, some people think that Jews came from the area now known as Israel. In the fifth century AD, some people think that Jews came from Majorca. [1] However, the first physical evidence of the presence of Jews in Kerala comes from much later, between the ninth and eleventh centuries AD, in the form of copper-plate inscriptions written by local kings. These inscriptions grant the local Jewish community certain rights. [2] Kollam and Kodungallur copper plates from AD 849 and AD 1000 show that there were trade guilds in Kerala made up of people from West Asia, like Jews and Persians. They also show that Kerala had a lot of people from other countries.
Source: https://www.sahapedia.org/cochin-jews-and-seven-synagogues-kerala-history-and-architecture