The best UML Modeling alternative to Dia is LibreOffice - Draw, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 50 alternatives to Dia and 19 are UML Modeling Tools so hopefully you can find a suitable replacement. Other interesting UML Modeling Tool alternatives to Dia are yEd Graph Editor, Lucidchart, PlantUML and Visual Paradigm.
Draw lets you produce anything from a quick sketch to a complex plan, and gives you the means to communicate with graphics and diagrams. With a maximum page size of 300cm by 300cm, Draw is a an excellent package for producing technical drawings, general posters, and much else.
Germany
EU
yEd is a powerful diagram editor that can be used to quickly create diagrams manually or import external data for analysis and auto-magically arrange even large data sets by just pressing a button. You can use yEd to quickly create flow charts, BPMN and UML diagrams...
GermanyEU
Lucidchart is a cloud-based platform that promotes teamwork through diagramming, collaboration, and data visualization. It serves millions worldwide, offering flowcharts, UML, real-time collaboration, Visio support, and browser access. Designed for innovation and understanding, it integrates easily into workflows.
United States
PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams. The generator can be run anywhere within JVM and integrated with various application such as wiki, text editor, IDE, programming language, documentation generator, and others.
FranceEU
Visual Paradigm for UML (VP-UML) is a UML design tool and UML CASE tool designed to aid software development. VP-UML supports key modeling standards such as Unified Modeling Language (UML) 2.4, SysML, ERD, DFD, BPMN 2.0, ArchiMate 2.0, etc.
Hong Kong SAR China
Gaphor is a WYSIWYG (What You See Is What You Get) UML and SysML modeling environment easy to use that will help you create your applications.
NetherlandsEU
Umbrello is a Unified Modelling Language (UML) modelling tool and code generator. It can create diagrams of software and other systems in the industry-standard UML format, and can also generate code from UML diagrams in a variety of programming languages.
GermanyEU
Lightweight, powerful, easy to use, UML tool
Software Ideas Modeler is a lightweight and powerful CASE tool. It supports UML 2.2 diagrams and a lot of other ones. Software Ideas Modeler is freeware (for non-commercial use). Commercial user may use this software only after buying.
SlovakiaEU
Web-based diagram platform offers real-time teamwork, 50+ diagram and mind mapping types, technical wireframing, smart objects, templates, version control, secure cloud storage, PDF export, collaboration tools, commenting, and integration for business and education use.
Australia
MagicDraw is an award-winning business process, architecture, software and system modeling tool with teamwork support. MagicDraw UML can do comprehensive UML diagramming, reverse and forward engineering for Java and C++.
Design flowcharts, UML, Venn, and mind map diagrams with customizable templates, varied symbols, shapes, connector styles, overlapping sheet support, and intuitive drag-and-drop editing. Export visuals as images, edit multiple diagrams, and organize complex data visibly.
Australia
ConceptDraw DIAGRAM v14 is the only product that supports Visio legacy, runs on macOS and Windows, and is a perpetual license. Import/Export VDX, VSDX, VSSX and Import VSD, VSS files.
Ukraine
