The main gateway is Pointe-à-Pitre International Airport (PTP), also called Pôle Caraïbes, located about 6km north of Pointe-à-Pitre on Grande-Terre. It handles direct flights from Paris (CDG and ORY), Montreal, Miami, and New York, as well as connections from other Caribbean islands. Air France, Corsair, and Air Antilles are the main carriers on the transatlantic routes. Flying time from Paris is around 8.5 hours; from Miami about 3 hours; from New York about 4.5 hours.
There is also a smaller airport at Basse-Terre (Marie-Galante Airport serves the outer islands), though most visitors arrive through PTP.
By ferry, Guadeloupe can be reached from Martinique (about 3 hours) and Dominica (about 2 hours) via L'Express des Îles, which operates daily catamaran services into Pointe-à-Pitre. This is a pleasant option if you're island-hopping through the eastern Caribbean.
Guadeloupe is a French overseas region, so EU citizens can enter with just a national ID card. Most other nationalities do not need a visa for stays under 90 days, though third-country nationals should check Schengen area entry rules, which apply here.