MotoGP organisers have made changes to their initial 2007 race schedule, including bringing forward the opening race at Losail in Qatar to 10 March.
Turkey and China have switched dates, with Istanbul the third race on 22 April and Shanghai following on 6 May.
The other change sees Portugal, which was originally the penultimate race, moving forward to 16 September.
There is still an increased 18-race programme, the extra date coming in San Marino on 2 September.
The season finishes in Valencia in Spain on 4 November while the British Grand Prix takes place at Donington on 24 June.
The opening race in Qatar and round nine in Holland on 30 June will both be run on Saturdays.
Moto GP calendar 2007:
10 March - Qatar (Losail)
25 March - Spain (Jerez)
22 April - Turkey (Istanbul)
6 May - China (Shanghai)
20 May - France (Le Mans)
3 June - Italy (Mugello)
10 June - Catalunya (Barcelona)
24 June - Great Britain (Donington)
30 June - Netherlands (Assen)
15 July - Germany (Sachsenring)
22 July - United States (Laguna Seca)
19 August - Czech Republic (Brno)
2 September - San Marino (Rimini)
16 September - Portugal (Estoril)
23 September - Japan (Motegi)
14 October - Australia (Phillip Island)
21 October - Malaysia (Sepang)
4 November - Valencia (Valencia)