To be clear, these all invest in equity REITs, which are real estate investment trusts that own commercial properties. You can also invest in mortgage REIT ETFs, an entirely different type of fund.
The Vanguard REIT Index Fund is the largest real estate ETF in the market by a wide margin. It tracks a weighted index of publicly traded REITs, meaning that larger REITs make up a larger part of the ETF’s assets.
The Schwab U.S. REIT ETF is similar in composition. It tracks an index of U.S. REITs, but with a few major differences from Vanguard. For example, the Schwab ETF doesn’t own the major communications REITs like American Tower (NYSE: AMT), as there's debate on whether these are telecom stocks.
The iShares Global REIT ETF is similar to the Schwab ETF in that it has non-telecom equity REITs. But it also invests in foreign REITs. These can add another layer of diversification and mitigate risks related to currency fluctuations and U.S.-specific economic weakness.
There are many other REIT ETFs, and most have a similar composition to the three listed here. These are my personal favorites because they represent three different investment strategies and have low expense ratios.
The bottom line
Investing in a REIT ETF lets you enjoy the high dividends, long-term growth opportunity, and portfolio diversification that comes with real estate investing. But it means you don't have to choose a particular REIT or property type. In a nutshell, it gives you the benefits of REITs without the guesswork or homework of choosing individual REITs.