diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -61,6 +61,7 @@
         loader.deposit=swh.loader.package.deposit:register
         loader.nixguix=swh.loader.package.nixguix:register
         loader.npm=swh.loader.package.npm:register
+        loader.opam=swh.loader.package.opam:register
         loader.pypi=swh.loader.package.pypi:register
     """,
     classifiers=[
diff --git a/swh/loader/package/opam/__init__.py b/swh/loader/package/opam/__init__.py
new file mode 100644
--- /dev/null
+++ b/swh/loader/package/opam/__init__.py
@@ -0,0 +1,17 @@
+# Copyright (C) 2021  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+
+from typing import Any, Mapping
+
+
+def register() -> Mapping[str, Any]:
+    """Register the current worker module's definition"""
+    from .loader import OpamLoader
+
+    return {
+        "task_modules": [f"{__name__}.tasks"],
+        "loader": OpamLoader,
+    }
diff --git a/swh/loader/package/opam/loader.py b/swh/loader/package/opam/loader.py
new file mode 100644
--- /dev/null
+++ b/swh/loader/package/opam/loader.py
@@ -0,0 +1,142 @@
+import io
+import os
+from subprocess import PIPE, Popen, call
+from typing import Iterator, List, Optional, Tuple
+
+import attr
+
+from swh.loader.package.loader import BasePackageInfo, PackageLoader
+from swh.storage.interface import StorageInterface
+
+
+@attr.s
+class OpamPackageInfo(BasePackageInfo):
+    pass
+
+
+class OpamLoader(PackageLoader[OpamPackageInfo]):
+    visit_type = "opam"
+
+    def __init__(
+        self,
+        storage: StorageInterface,
+        url: str,
+        opam_root: str,
+        opam_instance: str,
+        opam_url: str,
+        opam_package: str,
+        max_content_size: Optional[int] = None,
+    ):
+        super().__init__(storage=storage, url=url, max_content_size=max_content_size)
+
+        self.opam_root = opam_root
+        self.opam_instance = opam_instance
+        self.opam_url = opam_url
+        self.opam_package = opam_package
+
+        self.env = os.environ.copy()
+        self.env["OPAMROOT"] = opam_root
+
+        # if there's no opam_root at the expected path, we create a new one
+        # TODO: check that the opam_root is valid ?
+        if not os.path.isdir(opam_root):
+            if os.path.isfile(opam_root):
+                print("wrong opam root")
+                exit(1)
+            else:
+                call(
+                    [
+                        "opam",
+                        "init",
+                        "--reinit",
+                        "--bare",
+                        "--no-setup",
+                        opam_instance,
+                        opam_url,
+                    ],
+                    env=self.env,
+                )
+
+    def get_versions(self) -> List[str]:
+        proc = Popen(
+            [
+                "opam",
+                "show",
+                "--color",
+                "never",
+                "--normalise",
+                "-f",
+                "all-versions",
+                self.opam_package,
+            ],
+            env=self.env,
+            stdout=PIPE,
+        )
+        if proc.stdout is not None:
+            for line in io.TextIOWrapper(proc.stdout):
+                return line.split()
+                # we only care about the first line
+                # and there should be only one line anyway
+        print(
+            f"can't get versions for package {self.opam_package} \
+            (at url {self.url})"
+        )
+        exit(1)
+
+    def get_default_version(self) -> str:
+        proc = Popen(
+            [
+                "opam",
+                "show",
+                "--color",
+                "never",
+                "--normalise",
+                "-f",
+                "all-versions",
+                self.opam_package,
+            ],
+            env=self.env,
+            stdout=PIPE,
+        )
+        if proc.stdout is not None:
+            for line in io.TextIOWrapper(proc.stdout):
+                # we only care about the first element of the first line
+                # and there should be only one element and one line anyway
+                if len(line) == 1:
+                    return line.split()[0]
+                else:
+                    break
+        print(
+            f"can't get default version for package {self.opam_package} \
+            (at url {self.url})"
+        )
+        exit(1)
+
+        def get_package_info(
+            self, version: str
+        ) -> Iterator[Tuple[str, OpamPackageInfo]]:
+            proc = Popen(
+                [
+                    "opam",
+                    "show",
+                    "--color",
+                    "never",
+                    "--normalise",
+                    "-f",
+                    "url.src:",
+                    f"{self.opam_package}.{version}",
+                ],
+                env=self.env,
+                stdout=PIPE,
+            )
+            if proc.stdout is not None:
+                # filename is optional
+                yield OpamPackageInfo(
+                    url="https://...", filename="...-versionX.Y.tar.gz"
+                )
+
+            print(
+                f"can't get url.src for version {version} of package {self.opam_package} \
+                (at url {self.url})"
+            )
+            exit(1)
diff --git a/swh/loader/package/opam/tasks.py b/swh/loader/package/opam/tasks.py
new file mode 100644
--- /dev/null
+++ b/swh/loader/package/opam/tasks.py
@@ -0,0 +1,14 @@
+# Copyright (C) 2021  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+from celery import shared_task
+
+from swh.loader.package.opam.loader import OpamLoader
+
+
+@shared_task(name=__name__ + ".LoadOpam")
+def load_opam(url=None, artifacts=[]):
+    """Load Opam's artifacts"""
+    return OpamLoader.from_configfile(url=url, artifacts=artifacts).load()