By Air
India is well connected on world radar and there are several government and private airlines from different parts of the globe. There are 4 major international airports in India: Delhi, Mumbai, Kolkata and Chennai. Airports tend to be on the outskirts of cities. Pre-paid taxi services and auto-rickshaws are stationed outside the terminus to get you into the city.

By Road

From Nepal: from Nepal buses cross the border daily, usually with connections to New Delhi, Lucknow, Patna and Varanasi. However, it's cheaper and more reliable to take one bus to the border crossing and another from there on. The border crossings are (India/Nepal side) Sunauli/Bhairawa from Varanasi, Raxaul/Birganj from Patna, Kolkata, Kakarbhitta from Darjeeling, and Mahendrenagar-Banbassa from Delhi.

From Bhutan: The Royal Bhutanese Government runs a service to/from Phuentsholing. These buses depart from Kolkata's Esplanade bus station at 7PM on Tuesday, Thursday and Saturday and from the Phuentsholing Bhutan Post office at 3PM on Monday, Wednesday and Friday.

From Bangladesh: from Bangladesh there are a number of land entry points to India. The most common way is the regular air-conditioned and comfortable bus services from Dhaka to Kolkata via Haridaspur (India)/Benapole (Bangladesh) border post.

From Pakistan: From India you can cross into Pakistan at the international Attari/Wagah border.

By Rail
Railways do not cut across international borders in this part of the world except the Samjhauta Express that runs between Amritsar (India) and Lahore (Pakistan). But since the running of the train is subject to relations between the two countries it would be prudent to check if the train is running. However, in many cases it is possible to travel till the border by train.