LOS ANGELES (Reuters) - Walt Disney Co unveiled new single-day ticket prices on Saturday (Feb 27) for the company's US theme parks, switching to a three-tiered system that charges visitors more on the year's busiest days and less during typically slower periods.

The shift to demand-based pricing is designed to help spread out crowds at Walt Disney World in Florida and at Disneyland Resort in California, Disney said in a blog post.

Starting Sunday, a one-day ticket to Walt Disney World's Magic Kingdom will cost US$105 (S$148) on "value" days during slower periods, such as September.

The cost for "regular" days will be US$110. For "peak" days over major holiday periods, spring break and parts of the summer, the price will be US$124.

At Disneyland, the cost of admission to one park will be US$95, US$105 and US$119 for value, regular and peak days, respectively.

Value days will be most weekdays during the school year, while peak times are around holidays and weekends in July and December.

The previous one-day ticket prices were US$105 at the Magic Kingdom and US$99 at Disneyland.

The number of visitors to Disney's US parks set records in the October through December quarter, rising 10 per cent from a year earlier, the company said in its quarterly earnings report.

The busiest days create frustrations for visitors such as long lines and temporary gate closures when parks get too full.

The company is expanding the parks with new attractions based on popular franchises such as Star Wars and Frozen.

Disney said it will post eight- to 11-month calendars online that list which days fall in each pricing period.

Flexible pricing applies to one-day tickets only, it said, while charges for multiday tickets will not change based on attendance levels.