The smartphone market continues to be increasingly dominated by Apple (NASDAQ:AAPL) and Samsung, who are viciously battling to hold down their forts while grabbing share from each other. Kantar Worldpanel ComTech has released its most recent estimates for the three months ending in May, and each company is playing strong defense.

Samsung now has over half of the European market, which has helped drive Google (NASDAQ:GOOGL) Android's platform market share up to 70.4%. Android posted the biggest gain of all operating systems within the five biggest European markets, or EU5. Apple's market share in Europe slipped to 17.8%.

Apple has long enjoyed a strong user base in the U.S., much like other developed economies that utilize the subsidy model. Apple grabbed 41.9% of the market during the three months, its biggest slice of all the countries measured. The news comes after data that 57% of all smartphones activated on the top three domestic carriers in the first quarter were iPhones.

Kantar cites the addition of T-Mobile (NASDAQ:TMUS) as an iPhone carrier in helping Apple grow its domestic presence. The No. 4 carrier launched the iPhone in mid-April, meaning it was on sale for about half of the time frame in question. Kantar's data shows that 28% of T-Mobile customers are planning to by an iPhone for their next upgrade. T-Mobile's subscriber base may be smaller than its three larger rivals, but the pent-up demand from its customers are an incremental positive for Apple.

Corroborating data from IDC, Microsoft (NASDAQ:MSFT) has overtaken BlackBerry (NYSE:BB) as the No. 3 platform in numerous geographical segments. That includes the U.S., Europe, and Australia. Windows Phone's European market share of 6.8% is now well above BlackBerry's estimated 2.5%. Kantar estimates that BlackBerry's U.S. position has declined to just 0.7%, while Windows Phone now grabs 4.6% of the market.

The switch comes as no surprise considering BlackBerry's disappointing smartphone volumes and Nokia's rising Lumia shipments. Nokia is also helping Microsoft gain in the Mexican market with entry-level Windows Phones, although BlackBerry still has a firm lead over Microsoft south of the border.

Fool contributor Evan Niu, CFA, owns shares of Apple. The Motley Fool recommends Apple and Google. The Motley Fool owns shares of Apple, Google, and Microsoft. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.