Yes, Renfe (Spain’s national railway) prices fluctuate significantly in 2026, following a dynamic pricing model similar to airlines. For high-speed AVE and Avlo trains, tickets are released in "tiers." The cheapest fares, known as "Básico" or "Promo," are available in limited quantities when the booking window opens (usually 60 to 90 days in advance). As these seats sell out, the price for the remaining seats in the "Elige" (Pick) or "Prémiun" categories increases. In 2026, a ticket from Madrid to Barcelona might cost €25 if booked two months early, but could soar to €120 if purchased on the day of travel. Since the entry of competitors like Iryo and Ouigo into the Spanish market, Renfe has become even more aggressive with its price fluctuations to stay competitive. For 2026 travelers, the rule is simple: never wait until the last minute. Use the Renfe app or a consolidator like Trainline to track prices, as they rarely go down once they begin to rise, except during very rare flash sales or "low-occupancy" alerts.