To get in to the Customs department you need to get into the Indian Revenue Service (IRS). IRS constitutes Income Tax and Customs and Central Exercise. In the order to get into IRS, you have to clear the Civil Services Examination. The Civil Services Examination comprises:

Civil Service Aptitude Test (CSAT)
Civil Services Main Examination
Personality Test

Here are the details of Civil Services Examination:

Nationality:
A candidate must be a citizen of:
A citizen of India, or
A subject of Nepal, or
A subject of Bhutan, or
A Tibetan refugee who came over to India before 1st January, 1962 with the intention of permanently settling in India, or
a person of Indian origin who has migrated from Pakistan, Sri Lanka, Burma, East African countries of Kenya, Uganda, the United Republic of Tanzania, Zambia, Malawi, Zaire, Ethiopia and Vietnam with the intention of permanently settling in India.

Required qualification:
The applicant should have completed bachelors degree with good academic record from any recognized university of India………….

Age Limits
Candidate must have attained the age of 21 years and must not have attained the age of 30 years on 1st August