diff --git a/cwltool/docker.py b/cwltool/docker.py
index b1c1b7bbf..ee3472340 100644
--- a/cwltool/docker.py
+++ b/cwltool/docker.py
@@ -156,8 +156,8 @@ def get_image(
                 found = True
             elif "dockerFile" in docker_requirement:
                 dockerfile_dir = create_tmp_dir(tmp_outdir_prefix)
-                with open(os.path.join(dockerfile_dir, "Dockerfile"), "wb") as dfile:
-                    dfile.write(docker_requirement["dockerFile"].encode("utf-8"))
+                with open(os.path.join(dockerfile_dir, "Dockerfile"), "w") as dfile:
+                    dfile.write(docker_requirement["dockerFile"])
                 cmd = [
                     "docker",
                     "build",
diff --git a/cwltool/job.py b/cwltool/job.py
index 72488df7c..1502574a9 100644
--- a/cwltool/job.py
+++ b/cwltool/job.py
@@ -685,8 +685,8 @@ def create_file_and_add_volume(
         dirname = os.path.dirname(host_outdir_tgt or new_file)
         if not os.path.exists(dirname):
             os.makedirs(dirname)
-        with open(host_outdir_tgt or new_file, "wb") as file_literal:
-            file_literal.write(contents.encode("utf-8"))
+        with open(host_outdir_tgt or new_file, "w") as file_literal:
+            file_literal.write(contents)
         if not host_outdir_tgt:
             self.append_volume(runtime, new_file, volume.target, writable=writable)
         if writable:
@@ -1031,8 +1031,8 @@ def terminate():  # type: () -> None
             ) as job_file:
                 json_dump(job_description, job_file, ensure_ascii=False)
             job_script = os.path.join(job_dir, "run_job.bash")
-            with open(job_script, "wb") as _:
-                _.write(job_script_contents.encode("utf-8"))
+            with open(job_script, "w") as _:
+                _.write(job_script_contents)
 
             job_run = os.path.join(job_dir, "run_job.py")
             shutil.copyfile(run_job.__file__, job_run)
@@ -1041,7 +1041,7 @@ def terminate():  # type: () -> None
             shutil.copyfile(env_to_stdout.__file__, env_getter)
 
             sproc = subprocess.Popen(  # nosec
-                ["bash", job_script.encode("utf-8")],
+                ["bash", job_script],
                 shell=False,  # nosec
                 cwd=job_dir,
                 # The nested script will output the paths to the correct files if they need
diff --git a/cwltool/process.py b/cwltool/process.py
index f33ff0739..fa2338d3a 100644
--- a/cwltool/process.py
+++ b/cwltool/process.py
@@ -312,13 +312,11 @@ def stage_files(
                 shutil.copytree(entry.resolved, entry.target)
                 ensure_writable(entry.target, include_root=True)
         elif entry.type == "CreateFile" or entry.type == "CreateWritableFile":
-            with open(entry.target, "wb") as new:
+            with open(entry.target, "w") as new:
                 if secret_store is not None:
-                    new.write(
-                        cast(str, secret_store.retrieve(entry.resolved)).encode("utf-8")
-                    )
+                    new.write(cast(str, secret_store.retrieve(entry.resolved)))
                 else:
-                    new.write(entry.resolved.encode("utf-8"))
+                    new.write(entry.resolved)
             if entry.type == "CreateFile":
                 os.chmod(entry.target, stat.S_IRUSR)  # Read only
             else:  # it is a "CreateWritableFile"