diff --git a/.gitmodules b/.gitmodules
index a72a4f8..d9705e1 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,6 +1,3 @@
 [submodule "third_party/substrait"]
 	path = third_party/substrait
 	url = https://github.com/substrait-io/substrait
-[submodule "third_party/substrait-cpp"]
-	path = third_party/substrait-cpp
-	url = https://github.com/substrait-io/substrait-cpp
diff --git a/README.md b/README.md
index 4deeba2..9587aa0 100644
--- a/README.md
+++ b/README.md
@@ -136,12 +136,13 @@ relations {
 ```
 
 ## Load a Substrait Plan from JSON
-A substrait plan can be loaded from its JSON representation
-using the ``substrait.json.load_json`` and ``substrait.json.parse_json``
+A substrait plan can be loaded [from the JSON representation
+of the protobuf message](https://protobuf.dev/programming-guides/json/) using the [`protobuf` python library](https://pypi.org/project/protobuf/):
 functions:
 
 ```
->>> import substrait.json
+>>> from substrait.proto import Plan
+>>> from google.protobuf import json_format
 >>> jsontext = """{
 ...   "relations":[
 ...     {
@@ -182,7 +183,7 @@ functions:
 ...     }
 ...   ]
 ... }"""
->>> substrait.json.parse_json(jsontext)
+>>> json_format.Parse(text=jsontext, mesage=Plan())
 relations {
   root {
     input {
diff --git a/src/substrait/json.py b/src/substrait/json.py
deleted file mode 100644
index ed27d44..0000000
--- a/src/substrait/json.py
+++ /dev/null
@@ -1,25 +0,0 @@
-from google.protobuf import json_format
-
-from substrait.proto import Plan
-
-
-def load_json(filename):
-    """Load a Substrait Plan from a json file"""
-    with open(filename, encoding="utf-8") as f:
-        return parse_json(f.read())
-
-
-def parse_json(text):
-    """Generate a Substrait Plan from its JSON definition"""
-    return json_format.Parse(text=text, message=Plan())
-
-
-def write_json(plan, filename):
-    """Write a Substrait Plan to a json file"""
-    with open(filename, "w+") as f:
-        f.write(dump_json(plan))
-
-
-def dump_json(plan):
-    """Dump a Substrait Plan to a string in JSON format"""
-    return json_format.MessageToJson(plan)
diff --git a/tests/sql/test_sql_to_substrait.py b/tests/sql/test_sql_to_substrait.py
index ec33ee8..4b36431 100644
--- a/tests/sql/test_sql_to_substrait.py
+++ b/tests/sql/test_sql_to_substrait.py
@@ -1,6 +1,6 @@
 from substrait.sql.sql_to_substrait import convert
 import pyarrow
-import substrait.json
+from google.protobuf import json_format
 import tempfile
 import pyarrow.substrait as pa_substrait
 import pytest
@@ -91,7 +91,7 @@ def duckdb_schema_resolver(name: str):
         conn.install_extension("substrait", repository="community")
         conn.load_extension("substrait")
 
-        plan_json = substrait.json.dump_json(plan)
+        plan_json = json_format.MessageToJson(plan)
         sql = f"CALL from_substrait_json('{plan_json}')"
 
         substrait_out = conn.sql(sql)
diff --git a/tests/test_json.py b/tests/test_json.py
deleted file mode 100644
index 741bd87..0000000
--- a/tests/test_json.py
+++ /dev/null
@@ -1,71 +0,0 @@
-import os
-import pathlib
-import tempfile
-
-from substrait.proto import Plan
-from substrait.json import load_json, parse_json, dump_json, write_json
-
-import pytest
-
-
-JSON_FIXTURES = (
-    pathlib.Path(os.path.dirname(__file__))
-    / ".."
-    / "third_party"
-    / "substrait-cpp"
-    / "src"
-    / "substrait"
-    / "textplan"
-    / "data"
-)
-JSON_TEST_FILE = sorted(JSON_FIXTURES.glob("*.json"))
-JSON_TEST_FILENAMES = [path.name for path in JSON_TEST_FILE]
-
-
-@pytest.mark.parametrize("jsonfile", JSON_TEST_FILE, ids=JSON_TEST_FILENAMES)
-def test_json_load(jsonfile):
-    with open(jsonfile) as f:
-        jsondata = _strip_json_comments(f)
-        parsed_plan = parse_json(jsondata)
-
-        # Save to a temporary file so we can test load_json
-        # on content stripped of comments.
-        with tempfile.TemporaryDirectory() as tmpdir:
-            # We use a TemporaryDirectory as on Windows NamedTemporaryFile
-            # doesn't allow for easy reopening of the file.
-            with open(pathlib.Path(tmpdir) / "jsonfile.json", "w+") as stripped_file:
-                stripped_file.write(jsondata)
-            loaded_plan = load_json(stripped_file.name)
-
-    # The Plan constructor itself will throw an exception
-    # in case there is anything wrong in parsing the JSON
-    # so we can take for granted that if the plan was created
-    # it is a valid plan in terms of protobuf definition.
-    assert type(loaded_plan) is Plan
-
-    # Ensure that when loading from file or from string
-    # the outcome is the same
-    assert parsed_plan == loaded_plan
-
-
-@pytest.mark.parametrize("jsonfile", JSON_TEST_FILE, ids=JSON_TEST_FILENAMES)
-def test_json_roundtrip(jsonfile):
-    with open(jsonfile) as f:
-        jsondata = _strip_json_comments(f)
-
-    parsed_plan = parse_json(jsondata)
-    assert parse_json(dump_json(parsed_plan)) == parsed_plan
-
-    # Test with write/load
-    with tempfile.TemporaryDirectory() as tmpdir:
-        filename = pathlib.Path(tmpdir) / "jsonfile.json"
-        write_json(parsed_plan, filename)
-        assert load_json(filename) == parsed_plan
-
-
-def _strip_json_comments(jsonfile):
-    # The JSON files in the cpp testsuite are prefixed with
-    # a comment containing the SQL that matches the json plan.
-    # As Python JSON parser doesn't support comments,
-    # we have to strip them to make the content readable
-    return "\n".join(line for line in jsonfile.readlines() if line[0] != "#")
diff --git a/third_party/substrait-cpp b/third_party/substrait-cpp
deleted file mode 160000
index e26585f..0000000
--- a/third_party/substrait-cpp
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit e26585f45cdfd0ed3bf03f700c354f04685398c6
diff --git a/update_cpp.sh b/update_cpp.sh
deleted file mode 100644
index 804546a..0000000
--- a/update_cpp.sh
+++ /dev/null
@@ -1,5 +0,0 @@
-#!/bin/bash
-
-echo "Updating substrait-cpp submodule..."
-git submodule update --remote third_party/substrait-cpp
-