diff --git a/yt_dlp/extractor/_extractors.py b/yt_dlp/extractor/_extractors.py
index bb595f924b..da86caa740 100644
--- a/yt_dlp/extractor/_extractors.py
+++ b/yt_dlp/extractor/_extractors.py
@@ -1454,6 +1454,7 @@ from .onet import (
     OnetPlIE,
 )
 from .onionstudios import OnionStudiosIE
+from .onsen import OnsenIE
 from .opencast import (
     OpencastIE,
     OpencastPlaylistIE,
diff --git a/yt_dlp/extractor/onsen.py b/yt_dlp/extractor/onsen.py
new file mode 100644
index 0000000000..b5ca66aa2e
--- /dev/null
+++ b/yt_dlp/extractor/onsen.py
@@ -0,0 +1,151 @@
+import base64
+import contextlib
+import datetime as dt
+import json
+
+from .common import InfoExtractor
+from ..networking.exceptions import HTTPError
+from ..utils import (
+    ExtractorError,
+    clean_html,
+    int_or_none,
+    parse_qs,
+    str_or_none,
+    update_url,
+    url_or_none,
+)
+from ..utils.traversal import traverse_obj
+
+
+class OnsenIE(InfoExtractor):
+    IE_NAME = 'onsen'
+    IE_DESC = 'インターネットラジオステーション＜音泉＞'
+
+    _BASE_URL = 'https://www.onsen.ag'
+    _HEADERS = {'Referer': f'{_BASE_URL}/'}
+    _NETRC_MACHINE = 'onsen'
+    _VALID_URL = r'https?://(?:(?:share|www)\.)onsen\.ag/program/(?P<id>[^/?#]+)'
+    _TESTS = [{
+        'url': 'https://share.onsen.ag/program/onsenking?p=90&c=MTA0NjI',
+        'info_dict': {
+            'id': '10462',
+            'ext': 'm4a',
+            'title': '第SP回',
+            'cast': 'count:3',
+            'description': 'md5:de62c80a41c4c8d84da53a1ee681ad18',
+            'display_id': 'MTA0NjI=',
+            'media_type': 'sound',
+            'section_start': 0,
+            'series': '音泉キング「下野紘」のラジオ きみはもちろん、＜音泉＞ファミリーだよね？',
+            'series_id': 'onsenking',
+            'tags': 'count:2',
+            'thumbnail': r're:https?://d3bzklg4lms4gh\.cloudfront\.net/program_info/image/default/production/.+',
+            'upload_date': '20220627',
+            'webpage_url': 'https://www.onsen.ag/program/onsenking?c=MTA0NjI=',
+        },
+    }, {
+        'url': 'https://share.onsen.ag/program/girls-band-cry-radio?p=370&c=MTgwMDE',
+        'info_dict': {
+            'id': '18001',
+            'ext': 'mp4',
+            'title': '第4回',
+            'cast': 'count:5',
+            'description': 'md5:1d7f6a2f1f5a3e2a8ada4e9f652262dd',
+            'display_id': 'MTgwMDE=',
+            'media_type': 'movie',
+            'section_start': 0,
+            'series': 'TVアニメ『ガールズバンドクライ』WEBラジオ「ガールズバンドクライ～ラジオにも全部ぶち込め。～」',
+            'series_id': 'girls-band-cry-radio',
+            'tags': 'count:3',
+            'thumbnail': r're:https?://d3bzklg4lms4gh\.cloudfront\.net/program_info/image/default/production/.+',
+            'upload_date': '20240425',
+            'webpage_url': 'https://www.onsen.ag/program/girls-band-cry-radio?c=MTgwMDE=',
+        },
+        'skip': 'Only available for premium supporters',
+    }, {
+        'url': 'https://www.onsen.ag/program/uma',
+        'info_dict': {
+            'id': 'uma',
+            'title': 'UMA YELL RADIO',
+        },
+        'playlist_mincount': 35,
+    }]
+
+    def _perform_login(self, username, password):
+        sign_in = self._download_json(
+            f'{self._BASE_URL}/web_api/signin', None, 'Logging in', headers={
+                'Accept': 'application/json, text/plain, */*',
+                'Content-Type': 'application/json; charset=UTF-8',
+            }, data=json.dumps({
+                'session': {
+                    'email': username,
+                    'password': password,
+                },
+            }).encode(), expected_status=401)
+
+        if sign_in.get('error'):
+            raise ExtractorError('Invalid username or password', expected=True)
+
+    def _real_extract(self, url):
+        program_id = self._match_id(url)
+        try:
+            programs = self._download_json(
+                f'{self._BASE_URL}/web_api/programs/{program_id}', program_id)
+        except ExtractorError as e:
+            if isinstance(e.cause, HTTPError) and e.cause.status == 404:
+                raise ExtractorError('Invalid URL', expected=True)
+            raise
+
+        enc_id = lambda p: base64.b64encode(str(p['id']).encode()).decode()
+        query = {k: v[0] for k, v in parse_qs(url).items() if v}
+        if 'c' not in query:
+            entries = [self.url_result(
+                f'{url}?c={enc_id(program)}', OnsenIE,
+            ) for program in traverse_obj(programs, ('contents', lambda _, v: v['id']))]
+
+            return self.playlist_result(
+                entries, program_id, programs['program_info']['title'])
+
+        raw_id = base64.b64decode(query['c'] + '=' * (-len(query['c']) & 3)).decode()
+        p_keys = ('contents', lambda _, v: v['id'] == int(raw_id))
+
+        program = traverse_obj(programs, (*p_keys, any))
+        if not program:
+            raise ExtractorError(
+                'This program is no longer available', expected=True)
+        m3u8_url = traverse_obj(program, ('streaming_url', {url_or_none}))
+        if not m3u8_url:
+            self.raise_login_required(
+                'This program is only available for premium supporters')
+
+        display_id = enc_id(program)
+        upload_date = None
+        if date_str := self._search_regex(
+            rf'{program_id}0?(\d{{6}})', m3u8_url, 'date string', default=None,
+        ):
+            with contextlib.suppress(ValueError):
+                upload_date = dt.datetime.strptime(f'20{date_str}', '%Y%m%d').strftime('%Y%m%d')
+
+        return {
+            'display_id': display_id,
+            'formats': self._extract_m3u8_formats(m3u8_url, display_id, headers=self._HEADERS),
+            'http_headers': self._HEADERS,
+            'section_start': int_or_none(query.get('t', 0)),
+            'upload_date': upload_date,
+            'webpage_url': f'{self._BASE_URL}/program/{program_id}?c={display_id}',
+            **traverse_obj(program, {
+                'id': ('id', {str_or_none}),
+                'title': ('title', {clean_html}),
+                'media_type': ('media_type', {str}),
+                'thumbnail': ('poster_image_url', {url_or_none}, {update_url(query=None)}),
+            }),
+            **traverse_obj(programs, {
+                'cast': (('performers', (*p_keys, 'guests')), ..., 'name', {str}, filter, all, filter),
+                'series_id': ('directory_name', {str}),
+            }),
+            **traverse_obj(programs, ('program_info', {
+                'description': ('description', {clean_html}),
+                'series': ('title', {clean_html}),
+                'tags': ('hashtag_list', ..., {str}, filter, all, filter),
+            })),
+        }