Now that you have a foreign provisional patent application, you should look at your foreign business opportunities and decide which foreign countries in which to file. Your decision depends on (1) in which countries you will sell your invention and (2) your anticipated profits from those countries. The below information may help.
Canada - Many U.S. inventors also file in Canada because of its proximity and similarity to the U.S. for easier sales, and the filing cost, which is often under $5000.
Mexico - Depending on the product, Mexico is also a popular filing location due to its close proximity and busy commerce. Filing costs can vary widely, so multiple quotation searches can save money in the long run. Filing in South America should be considered only for proven business opportunities.
Asia - China is popular since much production occurs there and the Chinese middle-class has a significant growth rate. Japan is also popular as its market is both considerable and growing. Some people use the opportunity to combine business and a vacation (check with your tax advisor). Filing in China is comparable to filing in Canada, while filing costs in Japan are somewhat higher.
South Korea also has a growing middle class, but the Korean Patent Office (KIPO) tends to be protective of its home inventors, to the detriment of foreign patent owners.
Southeast Asia and India - Southeast Asia is popular for some markets, but patent owners will need to have a definitive presence, either personally or a reliable representative, to profitably monetize the patents. In spite of its rapid market growth, filing in India is a waste of money due to an extremely long period of time (many years) for a patent to issue.
Europe - Both the United Kingdom ($6000 and up) and the countries of the European Union (EU) are popular for foreign filings, due again to the similarities, and particularly for people who like to travel to Europe and use the opportunity to combine business and a vacation (check with your tax advisor). While a patent owner can file in the individual countries (except France) for about $4000 to $8000 per country (more or less), savings are possible with an initial filing at the European Patent Office (EPO). An EU patent has advantages if you want protection in several or more EU countries. First is a lower filing cost of about $8000 to $13000, compared to at least $16,000 for filing in four countries. Then there are lower costs in the interim between filing and issue as you pay for only one law firm to handle the application. There is also a benefit of not having to, and paying for, the work needed to track multiple patent applications.
Australia – the wonder down under is also a popular foreign filing location, again due to its similarities and lower costs, and its proximity to Asia which is a major trading partner for Australia. If you are making products in China for export, you should consider an Australian patent.
The Middle East, Gulf Coast Countries, Africa, Russia, and formerly associated countries - filing in these regions requires a definitive presence. Some of the Gulf Coast Countries can particularly be profitable, but local representation is recommended for all regions.
The final factor to consider is the annual fees. The U.S. requires post-issue fees three times during the 20 years of patent life. Most countries require annual fees called annuities, which vary by country from a modest cost of about $150 for the 2nd year to a few hundred dollars around the 5th year, to higher amounts in later years. Keep in mind that these are per year - per country. Four foreign patents can cost $1000 a year by the 4th year, but if you're working your patents to earn $100,000 per year, the cost is minimal.