diff --git a/bootstrap.fish b/bootstrap.fish
index 97eb75796..3e76063d5 100644
--- a/bootstrap.fish
+++ b/bootstrap.fish
@@ -83,7 +83,7 @@ set -e _pw_sourced
 set -e _PW_BOOTSTRAP_PATH
 set -e SETUP_SH
 
-# TODO(tonymd): Source fish pw_cli shell completion.
+source $PW_ROOT/pw_cli/py/pw_cli/shell_completion/pw.fish
 
 pw_cleanup
 
diff --git a/pw_build/py/pw_build/project_builder_presubmit_runner.py b/pw_build/py/pw_build/project_builder_presubmit_runner.py
index a42b1ac80..a0214bc95 100644
--- a/pw_build/py/pw_build/project_builder_presubmit_runner.py
+++ b/pw_build/py/pw_build/project_builder_presubmit_runner.py
@@ -638,7 +638,7 @@ def main(
     force_pw_watch: bool = False,
 ) -> int:
     """Build upstream Pigweed presubmit steps."""
-    # pylint: disable=too-many-locals
+    # pylint: disable=too-many-locals,too-many-branches
     parser = get_parser(presubmit_programs, build_recipes)
     args = parser.parse_args()
 
@@ -665,14 +665,18 @@ def main(
     else:
         charset = ASCII_CHARSET
 
-    if build_recipes and args.tab_complete_recipe is not None:
-        _tab_complete_recipe(build_recipes, text=args.tab_complete_recipe)
+    if args.tab_complete_recipe is not None:
+        if build_recipes:
+            _tab_complete_recipe(build_recipes, text=args.tab_complete_recipe)
+        # Must exit if there are no build_recipes.
         return 0
 
-    if presubmit_programs and args.tab_complete_presubmit_step is not None:
-        _tab_complete_presubmit_step(
-            presubmit_programs, text=args.tab_complete_presubmit_step
-        )
+    if args.tab_complete_presubmit_step is not None:
+        if presubmit_programs:
+            _tab_complete_presubmit_step(
+                presubmit_programs, text=args.tab_complete_presubmit_step
+            )
+        # Must exit if there are no presubmit_programs.
         return 0
 
     # List valid steps + recipes.
diff --git a/pw_cli/py/BUILD.gn b/pw_cli/py/BUILD.gn
index 2e4adde02..e29ad075a 100644
--- a/pw_cli/py/BUILD.gn
+++ b/pw_cli/py/BUILD.gn
@@ -43,6 +43,7 @@ pw_python_package("py") {
     "pw_cli/pw_command_plugins.py",
     "pw_cli/requires.py",
     "pw_cli/shell_completion/__init__.py",
+    "pw_cli/shell_completion/fish/__init__.py",
     "pw_cli/shell_completion/zsh/__init__.py",
     "pw_cli/shell_completion/zsh/pw/__init__.py",
     "pw_cli/shell_completion/zsh/pw_build/__init__.py",
@@ -63,7 +64,9 @@ pw_python_package("py") {
   mypy_ini = "$dir_pigweed/.mypy.ini"
   inputs = [
     "pw_cli/shell_completion/common.bash",
+    "pw_cli/shell_completion/fish/pw.fish",
     "pw_cli/shell_completion/pw.bash",
+    "pw_cli/shell_completion/pw.fish",
     "pw_cli/shell_completion/pw.zsh",
     "pw_cli/shell_completion/pw_build.bash",
     "pw_cli/shell_completion/pw_build.zsh",
diff --git a/pw_cli/py/pw_cli/__main__.py b/pw_cli/py/pw_cli/__main__.py
index f9eaa3768..3b543a3af 100644
--- a/pw_cli/py/pw_cli/__main__.py
+++ b/pw_cli/py/pw_cli/__main__.py
@@ -31,10 +31,15 @@ def main() -> NoReturn:
 
     pw_cli.log.install(level=args.loglevel, debug_log=args.debug_log)
 
-    # Print the banner unless --no-banner or --tab-complete-command is provided.
-    # Note: args.tab_complete_command may be the empty string '' so check for
-    # None instead.
-    if args.banner and args.tab_complete_command is None:
+    # Print the banner unless --no-banner or a tab completion arg is
+    # present.
+    # Note: args.tab_complete_{command,option} may be the empty string
+    # '' so check for None instead.
+    if (
+        args.banner
+        and args.tab_complete_option is None
+        and args.tab_complete_command is None
+    ):
         arguments.print_banner()
 
     _LOG.debug('Executing the pw command from %s', args.directory)
@@ -53,7 +58,7 @@ def main() -> NoReturn:
     if args.tab_complete_command is not None:
         for name, plugin in sorted(pw_command_plugins.plugin_registry.items()):
             if name.startswith(args.tab_complete_command):
-                if args.tab_complete_format == 'zsh':
+                if args.tab_complete_format in ('fish', 'zsh'):
                     print(':'.join([name, plugin.help()]))
                 else:
                     print(name)
diff --git a/pw_cli/py/pw_cli/arguments.py b/pw_cli/py/pw_cli/arguments.py
index 936dc1401..cac04b832 100644
--- a/pw_cli/py/pw_cli/arguments.py
+++ b/pw_cli/py/pw_cli/arguments.py
@@ -14,12 +14,13 @@
 """Defines arguments for the pw command."""
 
 import argparse
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from enum import Enum
+from functools import cached_property
 import logging
 from pathlib import Path
 import sys
-from typing import NoReturn
+from typing import Any, NoReturn
 
 from pw_cli import argument_types, plugins
 from pw_cli.branding import banner
@@ -41,39 +42,92 @@ class ShellCompletionFormat(Enum):
     """Supported shell tab completion modes."""
 
     BASH = 'bash'
+    FISH = 'fish'
     ZSH = 'zsh'
 
 
 @dataclass(frozen=True)
 class ShellCompletion:
-    option_strings: list[str] = field(default_factory=list)
-    help: str | None = None
-    choices: list[str] | None = None
-    flag: bool = True
+    """Transforms argparse actions into bash, fish, zsh shell completions."""
 
-    def bash_completion(self, text: str) -> list[str]:
+    action: argparse.Action
+    parser: argparse.ArgumentParser
+
+    @property
+    def option_strings(self) -> list[str]:
+        return list(self.action.option_strings)
+
+    @cached_property
+    def help(self) -> str:
+        return self.parser._get_formatter()._expand_help(  # pylint: disable=protected-access
+            self.action
+        )
+
+    @property
+    def choices(self) -> list[str]:
+        return list(self.action.choices) if self.action.choices else []
+
+    @property
+    def flag(self) -> bool:
+        return self.action.nargs == 0
+
+    @property
+    def default(self) -> Any:
+        return self.action.default
+
+    def bash_option(self, text: str) -> list[str]:
         result: list[str] = []
         for option_str in self.option_strings:
             if option_str.startswith(text):
                 result.append(option_str)
         return result
 
-    def zsh_completion(self, text: str) -> list[str]:
+    def zsh_option(self, text: str) -> list[str]:
         result: list[str] = []
         for option_str in self.option_strings:
-            if option_str.startswith(text):
-                short_and_long_opts = ' '.join(self.option_strings)
-                # '(-h --help)-h[Display help message and exit]'
-                # '(-h --help)--help[Display help message and exit]'
-                help_text = self.help if self.help else ''
-                state_str = ''
-                if not self.flag:
-                    state_str = ': :->' + option_str
+            if not option_str.startswith(text):
+                continue
 
-                result.append(
-                    f'({short_and_long_opts}){option_str}[{help_text}]'
-                    f'{state_str}'
-                )
+            short_and_long_opts = ' '.join(self.option_strings)
+            # '(-h --help)-h[Display help message and exit]'
+            # '(-h --help)--help[Display help message and exit]'
+            help_text = self.help if self.help else ''
+
+            state_str = ''
+            if not self.flag:
+                state_str = ': :->' + option_str
+
+            result.append(
+                f'({short_and_long_opts}){option_str}[{help_text}]'
+                f'{state_str}'
+            )
+        return result
+
+    def fish_option(self, text: str) -> list[str]:
+        result: list[str] = []
+        for option_str in self.option_strings:
+            if not option_str.startswith(text):
+                continue
+
+            output: list[str] = []
+            if option_str.startswith('--'):
+                output.append(f'--long-option\t{option_str.lstrip("-")}')
+            elif option_str.startswith('-'):
+                output.append(f'--short-option\t{option_str.lstrip("-")}')
+
+            if self.choices:
+                choice_str = " ".join(self.choices)
+                output.append('--exclusive')
+                output.append('--arguments')
+                output.append(f'(string split " " "{choice_str}")')
+            elif self.action.type == Path:
+                output.append('--require-parameter')
+                output.append('--force-files')
+
+            if self.help:
+                output.append(f'--description\t"{self.help}"')
+
+            result.append('\t'.join(output))
         return result
 
 
@@ -81,12 +135,7 @@ def get_options_and_help(
     parser: argparse.ArgumentParser,
 ) -> list[ShellCompletion]:
     return list(
-        ShellCompletion(
-            option_strings=list(action.option_strings),
-            help=action.help,
-            choices=list(action.choices) if action.choices else [],
-            flag=action.nargs == 0,
-        )
+        ShellCompletion(action=action, parser=parser)
         for action in parser._actions  # pylint: disable=protected-access
     )
 
@@ -99,9 +148,11 @@ def print_completions_for_option(
     matched_lines: list[str] = []
     for completion in get_options_and_help(parser):
         if tab_completion_format == ShellCompletionFormat.ZSH.value:
-            matched_lines.extend(completion.zsh_completion(text))
+            matched_lines.extend(completion.zsh_option(text))
+        if tab_completion_format == ShellCompletionFormat.FISH.value:
+            matched_lines.extend(completion.fish_option(text))
         else:
-            matched_lines.extend(completion.bash_completion(text))
+            matched_lines.extend(completion.bash_option(text))
 
     for line in matched_lines:
         print(line)
@@ -179,6 +230,7 @@ def arg_parser() -> argparse.ArgumentParser:
     )
     argparser.add_argument(
         '--debug-log',
+        type=Path,
         help=(
             'Additionally log to this file at debug level; does not affect '
             'terminal output'
diff --git a/pw_cli/py/pw_cli/shell_completion/fish/__init__.py b/pw_cli/py/pw_cli/shell_completion/fish/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/pw_cli/py/pw_cli/shell_completion/fish/pw.fish b/pw_cli/py/pw_cli/shell_completion/fish/pw.fish
new file mode 100644
index 000000000..d2751dd39
--- /dev/null
+++ b/pw_cli/py/pw_cli/shell_completion/fish/pw.fish
@@ -0,0 +1,82 @@
+# Copyright 2024 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+
+# Only generate completions if $PW_ROOT is set
+if test -z "$PW_ROOT"
+    exit
+end
+
+set status_message_length 0
+function print_status_message
+    printf '\033[s\033[1B\033[0G'
+    set -l status_message "Regenerating completions."
+    set status_message_length (math 1 + (string length --visible $status_message))
+    printf $status_message
+    printf '\033[u'
+end
+
+function print_status_indicator
+    printf '\033[s\033[1B\033['
+    printf $status_message_length
+    printf G
+    printf '.'
+    printf '\033[u'
+    set status_message_length (math $status_message_length + 1)
+end
+
+print_status_message
+
+complete -c pw --no-files
+
+# pw completion
+set --local --append _pw_subcommands (pw --no-banner --tab-complete-format=fish --tab-complete-command "")
+print_status_indicator
+set --local --append _pw_options (pw --no-banner --tab-complete-format=fish --tab-complete-option "")
+print_status_indicator
+
+# pw short and long options
+for option in $_pw_options
+    set -l complete_args (string split \t -- "$option")
+
+    complete --command pw --condition "__fish_use_subcommand; and not __fish_seen_subcommand_from $_pw_subcommand_names" $complete_args
+end
+
+# pw subcommands
+for subcommand in $_pw_subcommands
+    set --local command_and_help (string split --max 1 ":" "$subcommand")
+    set --local command $command_and_help[1]
+    set --local help $command_and_help[2]
+    set --append _pw_subcommand_names $command
+
+    complete --command pw --condition __fish_use_subcommand --arguments "$command" --description "$help"
+end
+
+# pw build completion
+if contains build $_pw_subcommand_names
+    set --local --append _pw_build_options (pw --no-banner build --tab-complete-format=fish --tab-complete-option "")
+    print_status_indicator
+    set --local --append _pw_build_recipes (pw --no-banner build --tab-complete-format=fish --tab-complete-recipe "")
+    print_status_indicator
+    set --local --append _pw_build_presubmit_steps (pw --no-banner build --tab-complete-format=fish --tab-complete-presubmit-step "")
+    print_status_indicator
+
+    complete --command pw --condition "__fish_seen_subcommand_from build" -s r -l recipe -x -a "$_pw_build_recipes"
+    complete --command pw --condition "__fish_seen_subcommand_from build" -s s -l step -x -a "$_pw_build_presubmit_steps"
+
+    for option in $_pw_build_options
+        set -l complete_args (string split \t -- "$option")
+
+        complete --command pw --condition "__fish_seen_subcommand_from build" $complete_args
+    end
+end
diff --git a/pw_cli/py/pw_cli/shell_completion/pw.fish b/pw_cli/py/pw_cli/shell_completion/pw.fish
new file mode 100644
index 000000000..2adf887f4
--- /dev/null
+++ b/pw_cli/py/pw_cli/shell_completion/pw.fish
@@ -0,0 +1,22 @@
+# Copyright 2024 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+
+# This script must be tested on fish 3.6.0
+
+set _pw_fish_completion_path (path resolve (status current-dirname)/fish)
+
+# Add the fish subdirectory to the completion path
+if not contains $_pw_fish_completion_path $fish_complete_path
+    set -x --append fish_complete_path $_pw_fish_completion_path
+end
diff --git a/pw_cli/py/setup.cfg b/pw_cli/py/setup.cfg
index 290b0a364..cbc9135db 100644
--- a/pw_cli/py/setup.cfg
+++ b/pw_cli/py/setup.cfg
@@ -34,8 +34,10 @@ pw_cli =
     py.typed
     shell_completion/common.bash
     shell_completion/pw.bash
+    shell_completion/pw.fish
     shell_completion/pw.zsh
     shell_completion/pw_build.bash
     shell_completion/pw_build.zsh
+    shell_completion/fish/pw.fish
     shell_completion/zsh/pw/_pw
     shell_completion/zsh/pw_build/_pw_build