diff --git a/swh/core/tarball.py b/swh/core/tarball.py
--- a/swh/core/tarball.py
+++ b/swh/core/tarball.py
@@ -22,12 +22,11 @@
 
     This expects the `extract_dir` to exist.
 
-    Raises
-
+    Raises:
         shutil.ReadError in case of issue uncompressing the archive (tarpath
         does not exist, extract_dir does not exist, etc...)
 
-    Returns
+    Returns:
         full path to the uncompressed directory.
 
     """
@@ -40,6 +39,29 @@
         )
 
 
+def _unpack_zip(zippath: str, extract_dir: str) -> str:
+    """Unpack zip files unsupported by the standard python library, for instance
+    those with legacy compression type 6 (implode).
+
+    This expects the `extract_dir` to exist.
+
+    Raises:
+        shutil.ReadError in case of issue uncompressing the archive (zippath
+        does not exist, extract_dir does not exist, etc...)
+
+    Returns:
+        full path to the uncompressed directory.
+
+    """
+    try:
+        run(["unzip", "-d", extract_dir, zippath], check=True)
+        return extract_dir
+    except Exception as e:
+        raise shutil.ReadError(
+            f"Unable to uncompress {zippath} to {extract_dir}. Reason: {e}"
+        )
+
+
 def register_new_archive_formats():
     """Register new archive formats to uncompress
 
@@ -72,6 +94,11 @@
         shutil.unpack_archive(tarpath, extract_dir=dest)
     except shutil.ReadError as e:
         raise ValueError(f"Problem during unpacking {tarpath}. Reason: {e}")
+    except NotImplementedError:
+        if tarpath.endswith(".zip"):
+            return _unpack_zip(tarpath, dest)
+        else:
+            raise
 
     normalize_permissions(dest)
 
diff --git a/swh/core/tests/data/archives/msk316src.zip b/swh/core/tests/data/archives/msk316src.zip
new file mode 100644
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

literal 0
Hc$@<O00001

diff --git a/swh/core/tests/test_tarball.py b/swh/core/tests/test_tarball.py
--- a/swh/core/tests/test_tarball.py
+++ b/swh/core/tests/test_tarball.py
@@ -241,3 +241,22 @@
             assert file.stat().st_mode == 0o100755
         else:
             assert file.stat().st_mode == 0o100644
+
+
+def test_unpcompress_zip_imploded(tmp_path, datadir):
+    """Unpack a zip archive with compression type 6 (implode),
+    not supported by python zipfile module.
+
+    """
+    filename = "msk316src.zip"
+    zippath = os.path.join(datadir, "archives", filename)
+
+    assert os.path.exists(zippath)
+
+    extract_dir = os.path.join(tmp_path, filename)
+    os.makedirs(extract_dir, exist_ok=True)
+
+    output_directory = tarball.uncompress(zippath, extract_dir)
+
+    assert extract_dir == output_directory
+    assert len(os.listdir(extract_dir)) > 0