How to open a KMZ file: three ways — Google Earth, QGIS or .zip

Someone sent you a .kmz file and it won't open on double-click — the system doesn't know what to show it with. Let's sort this out quickly: what the format is, three reliable ways to open it, and why it's often easier not to wrestle with someone else's KMZ but to download the area you need straight in a convenient format.

What KMZ is

KMZ is a ZIP archive with KML inside. KML (Keyhole Markup Language) is Google's text-based XML format for geographic data: points, lines, polygons, placemarks. To make the file smaller and let it carry attachments (icons, images, models), it's packed into a ZIP and given the .kmz extension. So KMZ is simply "compressed KML".

Three ways to open KMZ

1. Google Earth. The native app for KMZ. Use Google Earth Pro (desktop) or the web version — just open the file and the placemarks land on the globe. This is the simplest path if you only need to look.

2. QGIS. If you need to work with the data rather than just view it, use QGIS: Layer → Add Layer → Add Vector Layer → select the .kmz. QGIS reads the geometry and attributes, and from there you can style, measure and export to other formats.

3. Rename to .zip. Since KMZ is a ZIP, rename map.kmz to map.zip, unpack it with any archiver, and inside you'll get a doc.kml file (plus a folder of icons/images). KML is plain text — you can open it even in Notepad to inspect the contents.

A detailed technical breakdown of the format is in KMZ: a deep dive. KMZ specifically for Garmin devices is covered in the Garmin KMZ deep dive.

When it's easier to download your own map

Often people open a KMZ not out of curiosity but because they need a map of an area — and the file they got is the wrong territory, the wrong format, or cluttered with extras. In that case, don't bother with conversion: select the area you need and download it straight in a suitable format.

• KMZ — if the target app (Google Earth, GPS) expects KMZ;
• KML — the same format without packing, handy for text editing;
• GeoJSON — if the data goes into a web map or GIS.

You get a clean map of the right territory with OpenStreetMap layers, instead of figuring out someone else's file. It's free and takes seconds.

KMZ or KML — which to choose

If you'll edit the file or embed it in code, take KML (it's open text). If you're carrying it to a device or into Google Earth with icons, KMZ is more compact. The difference between KML and related formats is covered in GPX vs KML.

In short

• KMZ = a ZIP with KML inside; open it with Google Earth, QGIS, or by renaming to .zip.
• If you need a map of an area rather than someone's file — download it straight in KMZ, KML or GeoJSON.