In Wizards of the Coast material and without epic magic, a combination of effects can enable significant time travel
The 9th-level spell teleport through time [conj] (Perilous Gateways Web column "Portals in Time") allows one-way time travel backward up to 1,000 years. The spell's XP cost is acceptable, but the spell's material component is extremely difficult to acquire, and the spell's side effects are potentially deadly. No other nonepic spell that I'm aware of in and of itself causes instantaneous time travel of a year or more upon finishing its casting.
One-way time travel that's only forward can be achieved by employing the 5th-level Sor/Wiz spell plane shift [conj] (Player's Handbook 262) or a similar effect to travel to a plane with the planar trait faster flowing time (Dungeon Master's Guide 168) then simply waiting. However, such a plane must either already exist in the campaign's cosmology or the DM allowed the caster of the 9th-level Sor/Wiz spell genesis [conj] (Epic Level Handbook 117) to set a newly-created plane's flowing time trait (see here).
(Other methods of one-way forward time travel exist, but most occur on a 1:1 ratio while the traveler remains helpless—immersed in quintessence, for example, or petrified or as the subject of a temporal stasis effect. The consequences of an accident during such ersatz "time travel" can be severe.)
Still, a caster who can do both—somehow consistently cast the spell teleport through time despite its material component and travel to a plane with the faster flowing time planar trait—can effectively time travel.
Licensed and third-party material that may suit your needs
The Wizards of the Coast licensed product Legends of the Twins (Feb. 2006) for the Dragonlance campaign setting presents several spells dealing with time, including the 9th-level Sor/Wiz spell time reaver [trans] (27) that's easier to use than the teleport through time spell yet prohibits most folks (but not all folks!) who time travel using it from affecting the past. The third-party Encyclopedia Arcane supplement Chronomancy (Nov. 2002) details time travel rituals; these are complicated enough that getting the book is easier than me trying to explain them.